ENGINE TROUBLES AND REMEDIES
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Everything you've wanted to know about running and repairing old engines and then some!

SYMPTOMS, CAUSES, AND CORRECTIVES

ENGINE-STARTING AND RUNNING DIFFICULTIES

1. Defective action is sometimes due to causes so apparent that explanations are unnecessary; hence, for the sake of convenience all these possible sources of trouble have been grouped under the headings Causes of Refusal to Start, Causes of Misfiring, and Causes of Weak Explosions. In each case, the cause of the trouble may generally be traced in the last analysis to faulty ignition, a faulty mixture or an insufficient supply of mixture. These broad, ultimate causes have been stated first, and the principal mechanical or electrical defects that produce the trouble are enumerated afterwards. It will be understood that these do not comprise all the possible troubles with engines. In particular, they omit entirely such matters as preignition, knocking, and overheating. The object of the following presentation is to enable the user to trace the difficulty when his engine refuses to give its normal power through some trouble, the nature of which is not immediately obvious.

2. It is a familiar fact that the internal-combustion engine is far more liable to stoppages and weaknesses, for reasons at first mysterious, than is the steam engine. The explanation of this is that, while the steam engine is purely a mechanical apparatus, the internal-combustion engine is partly mechanical, partly chemical, and generally partly electrical in its functions, and the chemical and electrical parts of its organism may go wrong through causes not connected with the visible mechanism, or, as in the case of a badly adjusted trembler, a poorly working timer, or a leaky float, through mechanical derangements so slight as to escape notice.

From this it follows that, to manage successfully, an internal-combustion engine (especially one that works under such a variety of conditions, often very severe, as the automobile engine) it is first of all necessary for the operator to make good use of his reasoning faculties. The symptoms of derangement, when taken singly, are often such as may be caused by any one of several possible defects; in nearly every case the defect, whatever it may be, will produce several symptoms a careful study of which will lead to the elimination of causes that do not tally with all the symptoms; as, for instance, causes affecting all cylinders when only one or two are misbehaving, or vice versa. When the user has reached this point, generally a short further investigation of the points at which he has found trouble of that particular sort is most likely to occur will lead him to the discovery of the true cause. The cause of loss of power, due to such faults as a loose battery connection, a sticking inlet valve, or a bit of dirt in the carbureter, will at once be recognized in its true character by the experienced operator. The only way to attain final proficiency in these things is by extended experience with the particular engine in hand; but, on the other hand, there is absolutely no excuse for the aimless groping of many inexperienced users, who will often send needlessly for a tow, or will pull an engine to pieces in their search for some simple fault that might have been located by intelligent diagnosis.

3. Causes of Refusal to Start, or of Sudden Stoppage. - The fundamental reasons for an engine refusing to run, or of a particular cylinder refusing to work, may be summed up as due to (1) no spark; (2) no mixture; or (3) wholly wrong mixture. These cover all the possible causes, which may be enumerated as follows:

1. Switch not closed.
2. Gasoline not turned on.
3. Carbureter not primed, or (rarely) primed too much.
4. Weak battery.
5. Gasoline stale or mixed with kerosene.
6. Gasoline too cold to vaporize.
7. Dirt or waste in carbureter or gasoline pipe.
8. Mud splashed into air intake.
9. Water in carbureter.
10. Soot on the spark plug or contact igniter.
11. Water on spark plugs.
12. Broken spark-plug porcelain.
13. Grounded wire (generally secondary).
14. Broken wire (generally primary), or loose connection.
15. Very bad adjustment of the coil tremblers.
16. Defective spark coil or condenser (rare).
17. Broken igniter spring.
18. Broken valve stem, spring, or key.
19. Valve cams slipped (rare).
4. Causes of Misfiring.-The principal cause of misfiring is irregular sparking, which may be due to a variety of causes. Irregular sparking may be caused by the following:

1. Soot on spark plugs or contact igniters.
2. Weak battery.
3. Broken wire, making intermittent contact through the vibration of the engine (generally found in the primary circuit.
4. Loose connection to binding post (generally found in primary circuit).
5. Wire occasionally grounded through vibration of engine. This is generally found in the secondary circuit, and it is not necessary for the bare wire to make contact with the metal into which this secondary current is escaping. If the insulation of the secondary cable is weakened, and the cable is lying loosely on a metal part, the spark will often jump through the insulation.
6. Timer contact surfaces roughened by sparking.
7. Wabbling timer.
8. Poor trembler adjustment.
9. Trembler sticking at high speeds, due to inertia of heavy armature.
10. Insufficient pressure on timer contacts.
A sticking inlet valve, which stays open when it ought to close, will cause irregular firing and occasionally back firing. Another possible cause is a very lean or rich mixture ignitible only by a strong spark. It can always be distinguished from ignition troubles by the fact that the explosion impulses, when they occur, are of much less than normal strength. If the mixture is too weak, the explosions are likely to occur every other cycle.

5. Causes of Weak Explosions.-The causes of the explosions being weak are as follows:

1. Mixture too lean or too rich.
2. Leakage of compression.
3. Mixture diluted by exhaust gases.
4. Spark timing later than, it should be, in one or all cylinders.
If the trouble is in the mixture, the explosions would be regular, unless the mixture is so far defective that it sometimes fails to ignite in spite of the spark occurring regularly. The same will be true in any case where, as is usual, the cause of the weakness is unconnected with any irregularity in sparking.

The principal causes of 'weak explosions may be enumerated as follows:

1. Dirt or waste in carbureter or gasoline pipe, causing weak mixtures.
2. Stale gasoline.
3. Air intake partially obstructed, causing rich mixture.
4. Bad carbureter adjustment.
5. Trouble with float.
6. Choked muffler.
7. Lack of oil on piston, or too thin oil.
8. Leak through valve (generally the exhaust valve).
9. Leaky spark plug.
10. Valve timing wrong. This is most likely due to the fact that the cam-shaft, etc., have been taken out and replaced with the gears in incorrect angular relation. It may, however, be caused also by wear of the cams, push rods, or valve stems, by spring in the cam-shaft or valve lifters, or by the slipping of cams.
11. Broken or worn piston rings.
6. A two-cycle marine engine may be running along smoothly and begin gradually to slow down. This condition may be caused by too much or too little gasoline; the ignition devices may have become disarranged; there may be too little cylinder or other lubrication or too little water circulating through the cylinder jacket; something may be caught in the propeller wheel; in cool or cold weather, the moisture in the atmosphere may have become frozen by the rapid evaporation of the gasoline, thus preventing the free flow of air or the proper seating of the valve in the vaporizer controlling the gasoline supply and the flow of mixture from the crank-chamber; the piston and rings may have been fitted too snugly, causing them to bind in the cylinder, which may have become distorted by the different temperatures to which it is subjected, there being a comparatively cold inlet on one side of the cylinder and a hot exhaust port on the other; the exhaust ports, piping, or muffler may have become partly stopped by water, carbon, salt, or other deposits; the exhaust may have been submerged by a different trim of the boat, or there may have arisen conditions such as could not have been foreseen or provided against, and that might never again be experienced. At any rate, such slowing down is a forerunner of trouble and should be investigated. If the cause of the trouble cannot be discovered, the engine should be stopped when it is safe to do so, the position of the boat being made such as not to endanger either boat or occupants through collision with passing craft.

7. The remedies for slowing-down troubles due to the causes just mentioned will in practice suggest themselves. In many cases, the cause of the difficulty can readily be determined and overcome. For instance, trouble due to an insufficient quantity of cylinder oil or circulating water might be attended to readily without stopping the engine, or a temporary stop might be made to remove a rope, grass, etc., from the propeller, or foreign matter from the sea-cock strainer or pump check-valves, or to adjust the ignition or replace a broken or weak valve spring. Structural troubles, such as tight pistons and distorted cylinders, would have to be attended to at some more opportune time.

If the vaporizer should freeze, it may be necessary to run the engine awhile and then give the accumulation of ice and frost a chance to melt. If the water supply is insufficient and the jacket becomes overheated, it may be possible in case of an emergency to continue running by using a hand pump connected with the supply; or, with the supply open water may be pumped through or poured into the water discharge. In such case, the transformation of the water into steam might make it a little dangerous for the operator, and should the cylinder be too hot the water might possibly crack the cylinder at its weakest part, or at the point where it is subject to the greatest stress.

When it becomes necessary to run a four-cycle marine engine with too little circulating water, the compression should be relieved, the cooling action of the large quantity of gas, a part of which is wasted, helping to cool the cylinder, while the smaller amount exploded does not heat the cylinder as much as would full charges at the usual high compression pressure.

8. Irregular running of marine engines is a condition rarely encountered, and its cause is problematical. The trouble may be caused by back pressure in the exhaust, or may be due to improper location, with reference to the exhaust port, of the transfer, or passover, port connecting with the crank-case; this could occur only in two-cycle engines. As a result of such improper location of the port, the engine cylinder might not be thoroughly scavenged of 'burned gases at high speed, when it would slow down to normal speed or slightly below, and, getting a better mixture at that speed, would speed up. It might also be caused by the exhaust ports opening too late or the inlet ports opening too early. It is well known that, with no thought of fuel economy, two-cycle engine ports should open much earlier when designed for high than for low speed, in order to more thoroughly get rid of the products of combustion. When it is discovered that the engine is being run at a speed in excess of that to which it is best adapted, the remedy is to make the ports open earlier, or hold the engine to slower speed by increasing the diameter, pitch, or blade surface of the propeller.

Should the engine, without missing explosions, begin to increase its speed, and then miss explosions and slow down, one would naturally be led to suppose the cause of the trouble to be insufficient length of contact of the sparking device as well as poor scavenging of the cylinder.

Trouble from loss of compression in the combustion chamber, whether in a two-cycle or a four-cycle engine, must be remedied before the engine can be made to run satisfactorily. If, in attempting to start, it is found that there is no compression, the valves should be examined to see if they seat properly and are timed correctly. Loss of compression may be caused by a leaky gasket, allowing the pressure to leak into the water-jacket, which is the first place to look for the cause of trouble after examining the valves. A leaky, gasket may sometimes be discovered by noting whether or not pressure escaping into the waterjacket shows at the water discharge.

KNOCKING OR POUNDING

9. Undoubtedly the sense of hearing is more useful in detecting irregularities in the running of an engine than any other sense. By means of the sounds produced, the engine talks to the operator, and with a little intelligent study he will soon understand the language. Even at a distance it is often possible to tell whether an engine is running regularly or whether, as indicated by the sound of the exhaust, some of the charges admitted to the cylinder are expelled without being exploded. Standing in close proximity to the engine, the operator may distinguish a variety of sounds indicating defects about the engine and calling attention to the necessity of applying proper remedies 'at the first opportunity.

A sharp, knocking sound in stationary engines may be due to any one of the following causes:

1. Lost motion in the bearings of the connecting-rod, either at the crankpin or the piston-pin end.
2. Lateral movement of a piston ring, the groove in the piston having become widened by wear.
3. A loose key in the flywheel or pulley.
4. Lost motion in the gears, causing the gear-shaft to be retarded in its revolution for a fraction of a second when the exhaust or inlet-valve cam hits the roller and lever.
1 6. Piston or cylinder worn to a considerable extent, causing an up-and-down movement of the piston.
6. The piston having worn a shoulder in the bore of the cylinder, and striking the shoulder if any play in the bearings is developed.
7. The piston striking any foreign body that may accidentally have been drawn into the cylinder.
10. Knocking in engines may also be due to looseness or rattle in some external part, owing to nuts having worked loose or to bolts being sheared off or being too small for their holes. Knocking due to such causes is readily detected by a careful inspection while the engine is running, and this inspection may be aided by laying the hands on parts suspected of being loose, when vibration will easily be felt; also by careful scrutiny with an electric flashlight for evidences of movement where two parts are bolted together.

About the most likely place to find looseness of this description is in the holding-down bolts that hold the engine to the frame on which it is mounted; but in certain horizontal engines it way also be found that the caps over the main bearings are loose, owing to the fact that they have not been properly tongued into the bottom halves or pillow blocks of the bearings. Looseness at either of these two points should be remedied at the repair shop, as it always necessitates the substitution of larger bolts, aided perhaps by dowel-pins; and in the case of the bearing cap it may be necessary to make a wholly new cap, with proper tongues fitting into grooves that must be machined or chiseled in the pillow-block.

11. A more probable cause of knocking is looseness due to wear in the main-shaft bearings, crankpin bearings, or the wristpin bearings. In a four-cylinder vertical engine, the main-shaft bearings may be quite loose without causing a knock, because the weight of the shaft and flywheel holds the shaft down; but a horizontal engine will, under certain conditions of speed and load, pound with a small amount of looseness. Only a very limited amount of looseness should be permitted in the main-shaft bearings of any engine, both on account of the danger of springing the shaft and because a bearing worn beyond this extent is liable to begin cutting, as it is difficult to keep sufficient oil in it.

12. Looseness in the flywheel bearing of a vertical engine is disclosed by putting a jack under the flywheel and working it gently up and down. In the case of a horizontal engine it is necessary to move the shaft approximately in line with the pressure of the explosions, and a lever will have to be applied to the flywheel or shaft in whatever manner seems most practicable. Occasionally, looseness of the shaft can be detected by rocking the flywheel back and forth against the compression in the cylinder. If the pull of the sprocket chain comes on the engine shaft, it maybe possible to detect looseness in the adjacent bearing by alternately stretching and relaxing the chain, which can be done by grasping it midway between the sprockets and pulling it up and down as far as it will go.

A novice should not attempt to refit the main-shaft bearings, as this requires a good deal of skill and experience for its correct execution.

Wear in the crankpin bearings is disclosed by setting the cranks at about half stroke, and rocking the shaft back and forth.

13. Knocking in the wristpin, due to wear of the pin and its bushing, is not among the commoner troubles, and it does not need to be attended to at once unless aggravated. It is well, however, not to neglect it too long, as the bushings and the pin will be worn out of round, so that they cannot be used. When it is taken out, the wristpin should be calipered all around. If it is out of round, it should be ground true; or, if this is impracticable, a new pin will have to be supplied, and the bushing reamed or scraped to fit. This, of course, should be done in a repair shop.

14. A cause of knocking occasionally found is due to the wristpin and the crankpin not being quite parallel. This causes the connecting-rod to oscillate from end to end of the wristpin and crankpin bearings; and if, as is customary, there is 1/16 or more of end movement in these bearings, the knocking may be quite noticeable. If, as is likely to be the case, it is impossible to make the pins parallel, the only recourse is to take up the lost motion at the end of one or the other bearing, and possibly both bearings, by the use of washers or cheeks soldered to one end of the bushing and brasses. This is not a common cause of knocking, particularly in the better class of engines.

15. The best construction is to secure flywheels to short shafts by bolting them to flanges instead of keying them. Sometimes, however, a flywheel is held on by a common key, or by two keys 90' apart, and frequently it will work loose on its keys. This will inevitably result in a knock, which will be very loud if the engine has less than four cylinders. The crank-case should be opened and the cranks blocked so that the shaft cannot turn, and then force should be applied to the flywheel to disclose the looseness, if any. Sometimes the flywheel will be so tight on its shaft as to resist turning in this manner by using any ordinary force. In this case, it is best to take the engine to a repair shop if a thorough search has failed to disclose any other cause for the noise.

A sprung shaft will always cause knocking, and also rapid wear. and cutting of the bearings.

16. Besides the foregoing mechanical causes of knocking, there is a class of what may be called combustion knocks that are altogether distinct from the preceding, in that they may occur without appreciable looseness in the bearings, and are due to excessive rapidity of combustion, coupled generally with too-early ignition, the charge being completely burned before the piston has reached the end of the compression stroke. Combustion knocks are due to a variety of causes, the most obvious of which is simply too-early ignition, as when running a heavy load without suitably retarding the spark. A contributing cause is a slightly weak mixture, since such a mixture burns faster than a normal or overrich mixture. Pounding in particular cylinders of a multicylinder engine may be due to unequal rapidity of combustion, which itself may be due to unequal charges, as when the valves are unequally timed, or to irregular spark timing, such as may result from a wabbling timer or badly adjusted vibrators. If the timer contact surfaces have been roughened by sparking or by wear, they will cause the contact maker of the timer to jump when running fast, and therefore to make erratic contact, resulting in irregular firing.

17. The classes of combustion knocks just mentioned are easily traced to their causes. The knocks are not necessarily violent, and they may sound a good deal like the knocks due to loose bearings, except that, if caused by faulty action of timer or vibrators, they will occur irregularly instead of regularly.

There is, however, another and very common sort of knocking due to spontaneous ignition of the charge before the spark occurs. This may be caused by overheating of the engine from lack of water or other trouble with the circulation - a trouble at once indicated by boiling of the water in the radiator or by smoking of the exterior of the engine. It is a temporary phenomenon, and involves no harm to the engine if the latter is promptly stopped and allowed to cool.

18. Much more troublesome, and also more common, is spontaneous ignition, or preignition, as it is termed, due to a deposit of carbon in the combustion chamber or on the piston head. A carbon deposit of this nature may be caused by too much gasoline or by too much cylinder oil, and it will accumulate gradually even with the carbureter and lubrication correctly regulated. A small quantity of carbon will give no trouble, but as the deposit thickens some portions of it will remain incandescent from one explosion to the next, and will ignite the fresh charge at some point in the compression stroke, depending on conditions. The fact that the charge is not ignited until some time during compression is due to the fact that the more highly it is compressed, the more easily it ignites. True preignition results almost always, except at the highest engine speeds, in the charge being completely burned before expansion begins, and it is easily distinguished, especially if the engine is taking full charges, by the resulting sound, which is a sharp, metallic bing! bing! bing! closely resembling that produced by a hammer striking a block of cast iron. Usually, though not always, an engine that preignites in this manner will continue running by spontaneous ignition for some seconds after the igniter switch has been opened. The hammering due to preignition, as would be expected, is most marked when the engine is running slowly with the spark suitably retarded, and it will generally manifest itself under load, owing to the fact that the throttle is then wide open and the spark necessarily retarded to suit the slow speed of the engine.

19. In stationary engines, a heavy, pounding noise, such as is caused by premature ignition, may also be due to excessively high compression for the grade of fuel employed. In addition to its initial effect in producing a pounding noise, either preignition or a too-high compression pressure may cause the piston to expand unduly and to stick in the cylinder, which it would not do if the conditions were normal. This sticking of the piston would produce a knocking sound due to the small amount of play in the connecting-rod bearings necessary for smooth running. A coughing or barking sound is caused by the escape of pressure past the piston, and would indicate the necessity either of replacing any worn or broken piston rings or of reboring the cylinder and fitting a new piston.

With marine engines, a loose coupling may cause a pound, as may also a loose propeller wheel, but these pounds can easily be located.

CYLINDER AND PISTON DISORDERS

20. Scored and Leaky Cylinders. - One cause of scoring of the cylinder lies in the fact that the ends of the piston pin or wristpin when loose sometimes protrude through the hole or bearing in the piston. Some pins have their bearing in the piston itself, while others, being tightly secured in the piston, have their bearing in the upper end of the connectingrod. No matter which construction is employed, the ends of the pins should never come in contact with the cylinder walls. The pin must by some absolutely positive method be kept in place. While a loose wristpin is often the cause of a scored cylinder, there are three other causes, resulting from imperfections of design or of machine work, to which scoring can be traced; namely, loose core sand, imperfectly fitted piston rings, and loosening of the pins that are used to prevent the piston rings from turning in the slots in the piston.

21. Trouble from loose core sand Is due to sharp sand that usually comes from the cored passage connecting the crankcase with the inlet or passover port to the combustion chamber of two-cycle engines. With cylinder castings properly pickled in dilute sulphuric acid to remove the sand, this trouble would not be experienced; but with modern methods of cleaning castings by means of the sand blast, the cored passages are frequently neglected. Some engines are provided with a removable plate over the inlet port, for the express purpose of making sure that there shall be no core sand therein to cause trouble.

If, in an engine of the two-cycle type, the scoring consists of several parallel marks on the side where the inlet port is located, it is safe to ascribe the trouble to sand. If the scoring is on the exhaust-port side, it is usually an indication of insufficient lubrication; as the hot exhaust gases pass out they burn the oil off that side of the piston and cylinder, the exhaust side of a two-cycle engine cylinder being always hotter than the inlet side. Scoring may occasionally be due to the presence in the cylinder of pieces of the porcelain insulation of spark plugs. Cylinders have been practically ruined through rough dropping into the cylinder the pin or nut holding in place the spring on an inverted inlet valve.

22. Leaky cylinders (particularly in two-cycle engines) render the wristpin, crankpin, and main-shaft bearings subject to excessive wear, because the heat of the gases that pass by the rings into the crank-case tends to burn up the oil and heat the bearings. If the engine is of the two-cycle type, the leaking products of combustion not only foul the fresh charge of gas so that it is not so explosive, but the quantity of each charge is reduced.

If, in an engine in which the inlet and exhaust valves are tight and there is no leaky gasket, it is found that the compression has become materially reduced, the trouble is probably caused by leaks from distorted, scored, or imperfect cylinders, the pistons or piston rings being worn considerably or stuck in the slots in the piston. The only remedy is to remove the pistons for examination. If the cylinder is found to be out of round or scored, it will have to be rebored, and new pistons and rings fitted. If the rings are found to be rusted or stuck in the slots, they will have to be removed, even if to do so it is necessary to break them. They may have worn to such an extent that the openings at the points of parting are such as to allow a loss of pressure, the leaking charge passing either into the tight crank-case, if the engine is two-cycle, or into the atmosphere. If such leakage is not stopped, the heat of the escaping gases will burn the oil out of the crank-case, and the bearings will soon become badly worn, if not ruined.

23. The piston should be examined carefully for wear. The side on which the angular pressure of the connecting rod is exerted should, of course, show the most wear. If the front or rear side of the piston shows wear at top or bottom, with a corresponding amount of wear on the opposite bottom or top, it is proof that the hole through the piston for thepiston pin, to which is connected the upper end of the connecting-rod, is higher at the end showing wear at the top of the piston than at the end showing wear at the bottom. If this is found to be the case, and the wristpin is tightly secured in the piston, the connecting-rod bearing for the wristpin will be found to have worn badly and will be bell-mouthed, that is, larger at the ends than at the center. The remedy for this is to true up the bole carefully and bush it, or use a pin that is a trifle larger than the hole, increasing the size of hole in the tipper bushing slightly. This is a repair job that should be entrusted only to a thoroughly reliable machinist having the tools and means for doing accurate work. Side wear on the piston is much more likely to show in engines having the wristpin held securely in the upper end of the connecting-rod, the ends of the pin having bearings in the piston.

24. Piston rings become stuck in the slots in the piston from two causes; namely, from water getting into the combustion chamber, causing the rings to rust, and from the sides of the slots being slightly tapered instead of parallel. Where tapered sides are found, it is usually necessary to straighten them up in a lathe and use slightly wider rings, Piston rings should be renewed much oftener than is customary. As they become more and more open at the ends, the hot gases passing by the ends of the rings have a harmful effect on the polished, cylinder surfaces, and in two-cycle engines they foul the mixture in the crankcase.

25. Broken piston rings, particularly in engines with ports that are opened and closed by the pistons, are a source of annoyance, and frequently cause much trouble. Broken piston rings are frequently the result of insufficient care in putting the piston, with the rings in place, into the cylinder, but are more likely the result of getting a ring end caught in a port. To prevent this, two-cycle engine rings are usually pinned to prevent them from turning until the ends can get into the port.

The breaking of a piston ring is rather an unusual occurrence; it will cause loss of compression, that may be distinguished from leakage due to the rings being worn by the fact that the broken ring will make a distinct clicking sound at the end of every stroke. It will also be found that oil squirted on the piston when a ring is broken will not stop the leak. If the engine has more than one cylinder, it is probable that loss of compression due to lack of oil would affect all the cylinders, whereas a broken ring affects one only. If a piston ring is broken, it becomes necessary to take off the cylinder without delay and put in a new ring. Pinning Piston Rings

26. Piston rings are supposed to be held in position by small pins, one in each ring, so that the joints of adjacent rings are diametrically opposite. If for any reason these pins break, a ring may slip round until its joint is in line with that of the next ring above or below. This will cause loss of compression that may be very puzzling; it is an unusual occurrence, and it may be necessary to take off the cylinder to locate the trouble.

27. A good method for pinning piston rings is shown in Fig. 1 (a) and (b) Fig. 1 (a) is a diagram of a piston head, the dotted lines showing the bottom of the ring slot, while Fig. 1 (b) is a sketch of a portion of one side of the piston. With the piston square on its lower end, drill, at a, a point about half way between the inlet and exhaust ports, through b, c, and d, a hole large enough for clearance for a small tap, continue the hole into e with a tap drill, tap the hole, and screw into it a slotted screw to extend into the slot for a distance not quite one-half the width of the slot. Then tap and plug the hole through b, c, and d with screws dipped in muriatic acid to rust them in place, the screw plugs being in each case below the surface of the slot faces. At another point, where it would not come opposite a port, drill a hole through b and c and tap into d, plugging the clearance holes, as before. Drill at another point a hole through b, tapping into c. Slotted Piston Rings The slotted screws extend one-half or less the width of the slots from the bottom, so that, if the rings be parted as in Fig. 2 (a) one of the ends could be cut off slightly to receive the pin, or, if parted diagonally, as in Fig. 2 (b), a space could be cut out for the pin. With this method of (a) pinning the rings, there is no way for the pins to work out to score the cylinders. While it is customary to pin the piston rings for two-cycle engines, pins are rarely found necessary in four-cycle engines, as such engines have no ports to catch the ends of the rings, except when an auxiliary exhaust is employed.

28. Cylinder-Packing Troubles.-The joints between the cylinder head and the cylinder of stationary gas engines are kept tight by packings usually cut out of asbestos sheet about 1/32 inch thick. When the packing is damaged by overheating or excessive pressure, water from the jacket leaks either to the outside or into the cylinder. The latter is the more serious leak of the two, as it interferes with the running of the engine by corroding the points of contact on the igniter and the valve seats and stems, and prevents proper lubrication of the piston and cylinder. Leaking toward the cylinder i's generally indicated by splashing of the cooling water at the overflow pipe when the explosion takes place.

In most cases, the blowing out of a packing is caused by the combustion pressure opening the joint between the packing surfaces, the packing being heated and partly destroyed, and allowing water to enter the combustion chamber. A partial or complete stoppage of the coolingwater supply or the clogging of the water spaces with lime or similar deposits will also result in the overheating of the cylinder and consequent damage to the packings.

As soon as a leak of water from a faulty packing develops, preparations should be made to renew the packing at the first opportunity. If the leak is to the outside, which may not interfere with the operation of the engine, although it will cause inconvenience through having to catch the water in buckets, it is not necessary to shut down the engine until the day's work is done. If the leak is toward the combustion chamber, the engine will generally stop in a short time.

29. Many engines have the cylinder heads and cylinders in one piece; but a few engines have copper or aluminum water-jackets. There are, however, some old engines with separate heads still in service. In some cases, the cylinder beads, when separate, are made a ground fit on the cylinders, but they are commonly made tight by asbestos gaskets. Leakage through these may be detected some. times by the sound, and sometimes by putting a little oil over the suspected place and noting the resulting bubbles when the crank is turned.

In case a cylinder-head gasket leaks, it will be necessary to put in a new gasket. The head should be taken off, the old gasket removed, and the iron surfaces in contact with it should be carefully scraped clean. The new gasket may be of sheet asbestos, and it should be sprinkled evenly with powdered graphite to prevent it from sticking. It may be cut to size by laying it on the cylinder and tapping it lightly with a small hammer to indicate the outlines. Care should be taken not to let inwardly projecting edges interfere with the valves or igniters; and, also, if there are openings through the head for the passage of water, it should be seen to that these are not closed by the asbestos.

A good packing for cylinder heads is sheet asbestos with woven brass wire embedded in it. This packing is much stronger than ordinary sheet asbestos, and will not blow out unless the cylinder-head bolts are loose or the head is a bad fit. In replacing a cylinder head, the bolts should be tightened gradually and evenly, each being tightened a little at a time, and the round being made three or four times, so as to avoid localizing the stress on any one bolt.

There is, of course, but one remedy for leaky gaskets, namely, renewal. The old gasket should be carefully and completely removed, and by means of a straight edge a careful examination should be made to discover, if possible, why the gasket gave way at a particular point. There may have been insufficient surface or too little holding-down pressure to keep the packing in place; the studs may have been too far apart at the point of rupture, or the nuts may not have been tightened after the engine had become heated.

VALVE DERANGEMENTS

30. Leaky Inlet and Exhaust Valves.-Trouble from loss of compression in the combustion chamber, when the spark plug is tight and there is plenty of oil on the piston, is generally due to leaky valves. In order to determine whether the leak is in the valves or in the piston rings, a moderate quantity of oil may be squirted through the compression relief cocks and the crank turned two or three times, which will temporarily check whatever leakage there may be around the piston. If the compressed charge still escapes, the inlet valve, if located over the exhaust valve, may be taken out and examined. The leak, however, is much more likely to be in the exhaust valve. Valve

To take out the exhaust valve, turn the engine over by hand, with the switch off and the compression relief cocks open, until the valve is opened. Then prop up the valve spring with two pieces of wood or brass a, a, Fig. 3, cut to the proper length to go between the spring collar b, and the upper end (or lower end, if this is more convenient) of the push-rod guide c, and turn the engine again until the push rod d is down as far as it will go. Push the I exhaust valve down; the key at e may now be slipped out If the props have been made accurately to length, the valve may be slipped up and out, leaving the spring and the collar in place. Inspection should show the valve seat to be of uniform appearance all the way around, and dull - not glossy. If the seat of either valve is pitted or rough, or if it is worn bright on one side, showing that it has been seating only on that side, it should be reground.

31. The remedy for leaky valves is to regrind them to their seats. If badly scored and worn, which will be shown by a blackening of the seat and valve, it may become necessary to reseat and true up the valve, but if the engine has had ordinary care and attention, grinding should be sufficient. For this purpose, the exhaust valves may need emery and oil, finishing up with powdered oilstone, ground glass, silex, or the dirt that accumulates under a grindstone. The valve should not be rotated its whole circumference (as is frequently done, using a brace or breast drill with a bit screwdriver) but should be rotated a little, first in one direction and then in the opposite direction, raising it off the seat very often, and using oil freely, until a dull surface appears on both the valve and the seat throughout their bearing surfaces. Rotating the valve rapidly is very likely to cause grooves and ridges that are extremely hard to remove and make the valves tight.

While there is little or no danger of getting emery or other abrasive substance into the cylinder when grinding exhaust valves, ordinary care to avoid doing so should be exercised. The passage of the products of combustion being outwards, such matter would be carried away from the cylinder. Grinding the inlet valves is a very particular operation, for any particles of abrasive substance left behind to be drawn into the cylinder are liable to cause trouble. All traces of grindstone dirt, which will be found well adapted for grinding and may be mixed with water instead of oil, should be wiped off carefully.

The valve stems should be inspected, and, if rusted or rough, should be cleaned and smoothed, a few drops of kerosene being applied to cut any deposits that may have accumulated in the guides.

32. Weak or Broken Inlet-Valve Spring - Sometimes the inlet-valve spring, especially if the valve is of the automatic variety, will weaken from becoming overheated. This is almost sure to occur if the engine has been allowed to overheat from lack of water. In time, a spring loaded too near its elastic limit will break from the jarring to which it is subjected. The symptoms in either case are loss of power at high speeds (although the power may still be ample at low speeds) and clattering of the valve and blowing back in the intake pipe at high speeds. The latter may easily be detected with a single or double cylinder engine by holding the fingers close to the air intake, when the backwards puffing will be very perceptible. If the engine has four cylinders, it may be possible for the inlet valve springs to be slightly weak without the mixture blowing back at the intake, owing to the fact that one or another cylinder is aspirating all the time, and the air expelled from one cylinder is drawn into the next. One way to get around this difficulty is to block open the exhaust valves of two cylinders - the first and fourth or the second and third while the others are tested. It will probably be simpler, however, to experiment with the valve-spring tension. If the valve spring is weak, and if it is temporarily increased in stiffness by putting washers under it to compress it, a marked increase in the power of the engine at high speeds will be observed. The proper remedy, however, is to put in a new spring, or, if this cannot be done, to stretch the old spring, For a valve lift of 1/8 inch, and for average engine speeds, the tension should not be less than 1 pound per ounce of the weight of the valve, washer, and key. The engine will work better if the springs are a ttle too stiff than if they are not stiff enough. There will also be less danger of breakage of the valve stems and keys.

33. Unequal Tension of Automatic Inlet-Valve Springs.-The effect of unequal tension in the springs of automatic inlet valves is to permit one cylinder to take more gas than another. Consequently, at slow speeds the cylinder whose valve spring is weak will get the larger charge; and at high speeds part of the charge will be blown back through the valve whose spring is weak, so that the other cylinders will get stronger impulses. A quick way to test the equality of valve-spring tension without taking out the valves is to run the engine slowly with the throttle almost closed. This will cause the cylinders whose springs are stiffer to receive scarcely any gas, and the cylinders whose valve springs are weak will do most of the work. It is possible, however, to go to excess in a test of this sort, since, when an engine is running light with the minimum quantity of gas, one cylinder is almost sure to get more gas than another, if the inlet valves are automatic, even with the most careful equalizing of the springs. If the tension of the valve springs is under suspicion, the valves should be taken out and the springs tested by compressing the valve stems together.

34. Excessive Lift of Automatic Inlet Valve.-The lift of an automatic inlet valve should be proportionate to the spring tension and to the weight of the valve, so that the spring will be able to overcome the inertia of the valve, and close it before the piston has started so far on its compression stroke as to expel any of the mixture through the open valve.

The symptoms of too great a valve lift are loss of power and blowing back at high speeds. A valve 2 inches in outer diameter should not ordinarily lift more than 1/8 inch and a lift of 3/16 inch would be excessive for almost any valves found on high-speed engines. An excessive lift, like a weak spring, is likely to result in breakage of the valve stems and keys through unnecessary hammering of the valve when opening and closing.

35. Broken Inlet-Valve Stem or Key.-Trouble from a broken inlet-valve stem or key is more likely to occur with automatic valves than with those mechanically operated. The result, if the valve opens downwards, is to let it stay open all the time, causing that cylinder to cease work, while the sparks from the plug ignite the mixture in the intake pipe and cause explosions there and in the carbureter. If the valve, whether automatic or mechanically operated, opens upwards, it will clatter on its seat and permit much of the mixture to be expelled during the first part of the compression stroke.

36. Weak or Broken Exhaust-Valve Spring.-Owing to the heat to which it is subjected, the exhaust-valve spring is more likely to weaken than that of the inlet valve. The symptoms are loss of power, owing to the valve lingering open at the end of the exhaust stroke, and clattering when the valve closes.

37. Broken Exhaust-Valve Stem or Key.-As there is nothing to prevent the valve from being sucked wide open on the suction stroke, an accident of this kind will generally cause that cylinder to go out of action entirely. The clattering, if the engine continues running by virtue of other cylinders, is likely to be marked.

38. Slipped Valve Cams.-Some cheaply constructed engines have the valve cams held on the shaft by taper pins that in time shear partly or wholly through, permitting the cams to turn on the shaft. The cams may turn a short distance and then be jammed by fragments of the taper pins. The symptom indicating trouble due to this cause is partial or complete loss of power in the cylinder affected, when nothing is wrong with the ignition, valve-spring tension, etc.; and it will be equally marked at all speeds. If a cam is pinned on its shaft, the proper way to secure it is to add another pin, or, better, to add a key to take the torsional stress, and depend on the pin only to keep the cam from slipping endwise on the shaft.

LUBRICATION TROUBLES

39. Lack of Cylinder oil.- The symptoms of lack of cylinder oil are manifested in a sudden laboring of the engine, a dry or groaning sound, and partial loss of compression, followed by probable seizing of the piston. If the piston does not seize, it and the cylinder walls will at all events be scored.

Among the causes of lack of cylinder oil are clogging of lubricator by dirt or waste, obstruction in oil pipes, leaky check-valves, leaky pump packing, broken oil pipe, oil too cold to feed, lack of oil in crank-case, etc.

The remedies for trouble from this source will become obvious on inspection. The engine should be stopped and allowed to cool, and a liberal quantity of oil should be put in the crank-case before starting again. Squirt a little oil through the compression relief cocks to insure lubrication of the pistons, without waiting for oil to reach them from the regular sources. Remove the obstruction or repair the break as soon as possible.

40. Lack of Oil In Bearings.-A slightly loose main or crankpin bearing will sometimes be cut badly as a result of a temporary stoppage of oil feed, and yet give no noticeable symptom until the bearing is so badly cut that knocking begins. If a well-fitted bronze-bushed bearing becomes dry, it is more likely to stop or at least retard the engine. A babbitted bearing will melt out and let the shaft settle as far as other supports or bearings will allow. The result may be a violent pounding, a bent or broken shaft, or cut bearings generally, according to the particular conditions. There is no real safeguard against lack of oil in bearings except in the vigilance of the operator, combined with a system of oiling not liable to go wrong. It is not safe to depend on detecting a dry bearing by the sense of touch, because often the metal adjacent to bearings is sufficient to carry the heat away.

Generally, trouble from this cause is due to neglect to supply oil or to see that the sight feeds are working properly. It may also be due to a broken pipe, cold oil, etc.

There is no excuse for neglect to clean the oil strainer, or failure to inspect the oil pipes, unions, etc., or to know when starting out how much oil is in the crank-case. A badly cut bearing should be sent to a repair shop, and should be attended to without delay; but a bearing only slightly cut may be kept in service by the addition of a small quantity of flake graphite to the oil. If possible, the shaft should be taken out and polished with emery cloth and oil, else bronze from the bearing is likely to cling to it and aggravate the cutting. A bearing supplied with oil from a well beneath it, and a chain running over the shaft, may occasionally fail to receive oil owing to the chain catching on some internal roughness or projection in the oil pocket. It is always safest to keep a more or less regular supply of oil passing through bearings of this sort when in use, and depend on the oil well only as an equalizer.

41. Improper Oil In Cylinders.-The trouble symptoms produced by the use of oil unsuited for lubricating the piston are white or yellow smoke in the exhaust, rapid fouling of spark plugs, partial clogging of inlet and exhaust valves, and rapid accumulation of carbon on the valves in the combustion chamber and about the piston rings.

To remedy the trouble empty out all the unsuitable oil if possible, and substitute oil known to be good. Inject kerosene freely through the compression relief cocks to loosen the carbon deposit on the piston rings, and use kerosene to free the valves if they stick. Drain the crank-case, and, if possible, open it and clean out any carbon that may have worked down past the piston and mingled with the oil. Change all the spark plugs, and clean them when opportunity offers. Put in plenty of fresh oil before starting, and see that oil is supplied to the pistons so that they will not go dry before oil begins to feed from the cylinder lubricator.

42. Too Much Oil on Pistons.-Too much oil on the pistons is indicated by white smoke in the exhaust, fouled spark plugs and valves, substantially as when inferior oil is used, though the symptoms will not be so pronounced. An examination of the combustion chamber through the inlet valve or spark-plug hole, using a mirror and electric flashlight if necessary, will show an unnecessary amount of oil around the top of the piston. With the oil correctly regulated, it should not accumulate on the piston head in any great quantity.

Trouble from this source is remedied by drawing off part or all the oil from the crank-case, if it contains more than is necessary for running the engine, and reducing the oil feeds to the cylinders if necessary.

COOLING-SYSTEM TROUBLES

43. Lack of Water. - Lack of water in the radiator of the cooling system for engines is indicated by the rapid emission of steam, if there is sufficient water to enter the engine jacket; the bottom of radiator being cold; the overheating and smoking of the engine, followed by laboring, groaning sounds, owing to the oil being burned away faster than it is supplied to the pistons; and, if the engine still continues running, expansion and seizure of the pistons in the cylinders.

Trouble from lack of water is due to carelessness in not filling the tank before starting; leakage in radiator or piping; accidental opening of the drain cock at the lowest point of the circulation system; breakage of drain cock, etc.

The remedies for such trouble are apparent on inspection. If the engine becomes overheated so that the water boils rapidly away, and there is reason to think that the upper portion of the water-jacket is dry, the engine should be allowed to cool before water is added; otherwise, the sudden contraction may warp or even crack the cylinders, or it may cause the cylinders to contract and seize the pistons. The crank-case should be liberally supplied with oil to prevent the pistons from becoming dry, or, if a sight-feed oil cup is put on the cylinder, it should be set to feed quite rapidly. The engine should be stopped at the first sign of distress, as indicated by a groaning sound, turning with difficulty, or knocking caused by preignition due to hot cylinders.

44. Obstructed Circulation.-An obstruction to the circulation of the cooling water elsewhere than in the radiator will cause the bottom of the radiator to remain cool while the top is, probably, boiling hot.

Among the causes of obstructed circulation are a broken pump, broken driving connection to pump, or slipping belt or friction pulley, if the pump is driven in that manner; waste or the like lodged in the pump or piping.

The remedies for this trouble will become obvious on inspection. If the belt or friction pulley has oil on it, gasoline may be used to clean the pulley, as well as the flywheel if it drives the pulley.

45. Scale or Sediment In Radiator.-The presence of scale or sediment in the radiator is indicated when the whole radiator becomes hot or when steam formed in the jacket forces water out of the upper pipe to the radiator, there being no oil on the inside or dirt on the outside of the radiator.

Scale will deposit from hard water if the temperature of the water is allowed to approach the boiling point. A similar scale, almost impossible to eliminate, will crystallize from calcium-chloride non-freezing mixture; if these are allowed to become supersaturated.

A radiator badly choked with lime scale is practically hopeless, although, if it is made entirely of brass and copper, it may sometimes be helped by the use of a dilute solution of hydrochloric acid in the proportion of about one of acid to ten of water. This should be left in the radiator long enough only to loosen the scale, and should then be drawn off, and the radiator washed out. It is better in doing this to disconnect the radiator from the engine, in order to confine the effects of the acid. Another method is to use washing soda. Ordinary dirt maybe cleaned out by a strong, hot solution of lye, which should be used with care, as it burns the skin badly. Rainwater should be used wherever possible, and all the water should be strained.

46. Dirty Radiator.-When the whole radiator is hot and it is impossible to run without boiling the water, the circulation being good, it is evident that the radiator is dirty.

Flying oil about the engine may lodge on the air surfaces of the radiator tubes, and gather dust, which forms a nonconducting covering. Oil sometimes gathers on the water surfaces by gradual escape from the pump bearings, or may remain after an attempt to substitute refrigerator oil for water as a cooling medium in freezing weather. The film of oil, preventing the water from coming in contact with the metal, acts practically as an insulator.

To remove the oil from the radiator use kerosene, or a mixture of 'kerosene and mineral-oil soap. Dissolve the soap in water and add it to the kerosene, fill up the radiator with the mixture, and run the engine for an hour or more until the radiator gets well heated. The soap and kerosene will form an emulsion with the oil, and when the mixture is hot it may be drawn off and the radiator washed out with cold water. For the removal of the external oil and dirt, use gasoline, with a brush or swab.

A simple trouble, but one likely to be mistaken by the novice for radiator or circulation trouble, is slipping of the fan belt. The belt should be tested occasionally, and not allowed to get so loose that the fan pulley can spin inside it. It does not need to be tight.

CARBURETER DISTURBANCES

PROPORTIONING OF MIXTURE

47. Overrich MIxture. -If a mixture is very rich, that is, if there is an excessive amount of gasoline in the charge, the fact will be manifested by black smoke in the exhaust. If the mixture is not rich enough to produce smoke, it will still produce an acrid odor in the exhaust, and will cause overheating of the radiator, unnecessary sooting of the plugs, accumulation of carbon in the combustion chamber, and unnecessarily rapid comsumption of gasoline, with diminished power.

The causes of an overrich mixture are: faulty carbureter adjustment; leaky float; leaky float valves; float too high on its stem or too heavy; spray nozzle loosened or unscrewed by vibration; and dirt on the wire-gauze screen over the mouth of the air-intake pipe. For float troubles, see paragraphs. 52 to 55, inclusive.

48. Flooding is the most common source of trouble in marine engines using vaporizers. It is caused by leakage of gasoline into the vaporizer, from which in a two-cycle engine it readily runs into the crank-chamber; the resulting mixture is too rich in gasoline, and, not having sufficient oxygen, is unexplosive. When trouble from flooding is suspected, turn the engine over two or three times, with the gasoline valve and the switch closed. If there is an explosion, note the color of the flame at the relief cock, or priming cup, which should be left open for the purpose, If no explosion occurs, leave the cock or cup open and slowly turn the flywheel to a point just before the exhaust port opens, thus drawing air into the cylinder through the priming cup to dilute what is thought to bean overrich mixture. Now revolve the flywheel in the opposite direction rather rapidly until the spark occurs. If there is no explosion, try again, and repeat the operation two or three times if necessary. If an explosion then takes place, it is evident that flooding is present.

To remedy this in a two-cycle engine, open the draw-off, or drain cock in the lowest part of the crank-case, and draw off the contents, taking care, however, to replace with a fresh supply the lubricating oil thus drawn out. If there is no draw-off cock, it will be necessary to turn the flywheel many times to exhaust the excess of gasoline in the crank-case, leaving the switch closed and the compression relieved as much as possible. Af ter a while, an explosion should take place, then another, gradually becoming more frequent, until finally the engine may run with an explosion at every other revolution or so. The gasoline valve should be kept closed until the charges explode regularly and the red tinge to the flame at the relief cock and smoky exhaust disappear, after which the gasoline may be turned on and regulated at the needle valve in the vaporizer, closing it slightly at first; and, if the engine slows down somewhat, open it slightly until it is possible to tell whether it is getting too little or too much gasoline.

In case of flooding in a four-cycle engine using a vaporizer, two or three revolutions of the crankshaft will usually dispose of any excess of gasoline, for there cannot be as large an amount in the exhaust piping of a four-cycle engine as could accumulate in the crank-case of a two-cycle engine. Trouble from flooding in a two-cycle engine is the first thing to be suspected when an engine of that type refuses to start readily.

If the cause of a failure to start is found to be an insufficient supply of gasoline, due to dirt in the needle valve, or to a small amount of water in the gasoline piping, lift the valve in the vaporizer from its seat and let a little gasoline run through to clear the obstruction or get a drop or two of the water out, being sure to catch the drip for examination. If there is any water it will show in globular form at the bottom of the vessel. In case water is found, the pipe must be disconnected and drained, and any water in the tank must, if possible, be removed, for a single drop of water will completely close the aperture in the seat of a needle valve.

49. Weak Mixture.-Among the symptoms produced by a weak mixture are insufficient power, although the explosions are regular; a tendency to preignite or to burn very rapidly if there is the slightest carbon deposit; the engine sometimes will miss every other explosion. There is likely also to be difficulty in starting the engine. It is not always easy to distinguish between lack of power due to an overrich mixture and that due to a weak mixture, but the tendency of the former is to produce black smoke and of the latter to preignite and Miss explosions. Some experimenting with the carbureter adjustment will often be necessary to settle the point.

Nearly all the causes named in paragraph 47 will make a mixture richer at some speeds than at others, and if the carbureter has been readjusted, for example, in the attempt to correct trouble due in reality to a heavy float, the result will be to make the mixture faulty again at certain other speeds. Special causes of weak mixture are dirt or waste in the gasoline pipe or strainer; stale gasoline; carbureter too cold to vaporize; dirt in the spray nozzle; float too light or too low on its stem.

For float-trouble remedies see paragraphs 52 to 55, inclusive. Experimenting with the carbureter adjustment should be very cautiously done, with the original setting or adjustment marked so that it can be restored if necessary. The carbureter should then be adjusted slightly in one direction or the other, and the effect noted before further change is made. Very often a combination of adjustments will be necessary, but it is best to make them one at a time. If a radical change is made it may be very difficult to start the engine at all, and this would leave the experimenter completely in the dark as to what was required.

DIRT IN CARBURETOR AND GASOLINE PIPING

50. Dirt In Carbureter.-If there is dirt in the float valve, it will prevent the latter from closing and will cause the carbureter to flood. This will produce an overrich mixture, especially at low speeds, and is highly dangerous on account of the liability to fire. If the dirt is in the spray nozzle, it will produce a weak mixture. If the dirt has been splashed into the air intake, it will produce an overrich mixture, especially it high speeds.

The remedies for trouble due to dirt in the carbureter will become obvious when the nature of the trouble is located. A carbureter that has previously worked well and that suddenly begins to leak has in all probability dirt in the float valve. A carbureter that suddenly gives a very weak mixture has dirt probably in the gasoline pipe, strainer, or spray nozzle.

51. Dirt or Waste in Gasoline Pipe.- Dirt or other obstructions sometimes accumulate, especially if the gasoline has not been properly strained. The symptom is a sudden or gradual weakness of the mixture, necessitating readjustment of the carbureter in order to keep the engine running. The most probable place of lodgment for obstructions of this sort is in the gasoline line pipe where the latter connects to the carbureter, or in the strainer, through which the gasoline generally passes just before it enters the float chamber. Disconnecting the gasoline pipe or the union exposing this strainer will generally disclose the obstruction. Sometimes it may be necessary to disconnect the gasoline pipe at both ends, and blow it out. This is necessary only when the pipe has been disconnected near the carbureter and gasoline does not flow freely from it when turned on at the tank.

FOAT TROUBLES

52. Leaky Float Valve.-With a leaky float, the carbureter drips when the main gasoline valve is opened. The leakage is not stopped when the top of the float chamber is opened and the needle valve pressed down with the finger, or when the mixing chamber is opened and the spray nozzle covered with the finger.
To remedy the trouble grind in the valve with pumice or fine sandstone.

53. Float Too High.-By the expression float too high is meant that the float is set too high on its stem so that it is not lifted by the gasoline sufficiently to close the float valve before gasoline escapes from the spray nozzle.

When this trouble is present, the carbureter drips when the main gasoline valve is opened; but the float valve is soon closed by the float if the spray orifice is covered by the finger. The float valve closes tight when manipulated by the fingers, or when the float is lifted by a pair of bent wires, When the trouble is due to a high float, it will be found that the float itself is empty, and, if of cork, that it not gasoline soaked.

Unless the float is adjustable on its stem, the easiest remedy for this trouble is to bend the levers by which the float acts on the float valve. If this cannot be done, shift the float 1/16 inch lower on the stem by the use of a soldering iron.

54. Float Too Heavy. --The same symptoms are present when the float is too heavy as when the float is too high, but they are caused generally by a leak in the float or by its being gasoline-soaked.

If the float is hollow, it will sometimes be found that there is present in it a minute leak due generally to some oversight in soldering. If the float is taken out and shaken with the hand, the presence of the gasoline inside of it will at once be apparent. The float should be immersed in warm water until all the gasoline in it is slowly boiled away and its vapor has been expelled through the aperture in the float, By holding the float under water, the escape of bubbles will indic
Each of my posts is a sincere attempt to correlate & compound the collective knowledge of this community for the benefit of myself & all Mach1 owners who read these pages today, and in the future!
Welcome all Mach1 enthusiasts were glad your here! Jump on in and spread all the knowledge you can.Rockxtreme


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Great reference check. I am sure I had at least one of each of these problems in past. I will definatley hang this on the wall right next to where I usually bang my head!! Thanks for sharing.
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