Mach 1 Club

Hi
When starting the Engine it goes around 1000 rpm at idle, then I put it in drive. When putting it back in P the Engine revs up to 1500 rpm and it stucks there. Whats wrong ?

Regards Rob

At a guess the idle up cam on the choke is sticking or badly adjusted.

Ok

I dont really know where to look, but the spring if there should be a spring in this thing. Does not work. If I force it by hand its stays there..



Here is the Mach btw



Regards Rob

The item you have circled is a solenoid to increase the idle. Back then, they were used for either increasing the idle speed when the A/C is turned on, or to prevent engine run-on when you shut off the engine. Engine run-on is what most people refer to as dieseling. Simply, the engine tries to keep running after you shut off the ignition switch. Fortunately for your case it is probably used to increase the idle when the A/C is turned on. It could be that, or choke adjustments, or sticking choke linkage.

Before determining if that solenoid is bad, does the car have functioning A/C on it? If not, do you plan to fix and use the A/C?

Best Regards,
Mike

The AC compressor is out of the car, I have no plans for restoring it. On the left side there is a vacuum Clock or something with a linkage , what is that ?

Regards Rob

First, if you do not intend on reinstalling the A/C I would remove that solenoid and bracket assembly (the item you have circled in the photo).

You say vacuum clock looking item on the other side. I think you are referring to the round item with the black plastic cap. That is the choke assembly. Inside the black plastic cap is a bymetal coiled spring that when heated unwinds and opens the choke. It was originally heated by a tube that went to the passenger side exhaust manifold.

But, I think from another thread your car has headers. The headers eliminated the hot air tube that attached to the passenger side exhaust manifold. Without that the choke will not operate and will always stay closed causing a fast idle. There used to be available a hot air tube kit that clamped onto a header tube and connected to your choke but I have not seen any recently. Most people work around that by changing over to an electric choke or eliminating the choke. An electric choke looks very similar but is heated electrically.

I think you possible have a couple issues going on.

- First, remove the solenoid you have circled in the photo to eliminate it from possibly holding the throttle open.

- Second, your choke is not being heated, so I suspect it is never opening. You can manually adjust the choke so it will stay open all the time. Simply loosen the three screws that hold on the black plastic cap. Then rotate the cap until the choke butterfly stays fully open and retighten the three screws. I don't recall if it is clockwise or counterclockwise you'll have to experiment. If you do this you will have to work the gas pedal until the engine is warm enough to idle on its own. It can be a pain.

- If you do both of the above items you may have to readjust the idle speed when the engine is hot. It may have never been set originally.

If you do any of these, post the results so we will know what happened.

Holley makes electric choke conversion kits and electric choke caps ( the black plastic part) for their carbs but I do not know if the electric components of the will fit your Autolite carb. Maybe somebody else knows an easy way to convert it to an electric choke will chime in. The expensive solution is a new Holley two barrel carb with an electric choke. But where do you stop, leave it 2-barrel, convert it to 4-barrel with a new intake manifold as well? It can be a slippery slope.

In case you are unaware, just for safety, it's a good idea to have the air cleaner installed when starting a motor and you are uncertain how it will react. If there is a backfire through the carb the air cleaner will prevent it from damaging anything or injuring anybody. Also, don't stand in front of the car with a motor running without an air cleaner installed. If it backfires a flame tends to hit the hood then travel towards the front of the car.

Finally a quick FYI, for your future reference when buying parts, etc. the normal convention is the drivers side of the car is the left side and passenger side of the car is right side . At least in the US it's that way.

Best Regards,
Mike

Thanks for an xlnt post ! It was a combination between 2 things.
First the solenoid, I removed it and it was a big difference. Now the Idle was much better but still a bit harsh. I brought a friend over that is a professional hotrod builder. He could directly se what was wrong. The axel is not centered in the carb, thats why.
Im gonna change to edelbrock carb, manifold, new Cables, etc so in a week or two Im gonna take it to his garage

Thanks again for all help.

Regards Rob

Thanks Steven

I was thinking an 2750 edelbrock manifold
edelbrock cf 600 carb
Petronix ignitor
and new Cables

Regards Rob

(05-05-2015, 01:26 AM)RobSweden Wrote: [ -> ]Thanks for an xlnt post ! It was a combination between 2 things.
First the solenoid, I removed it and it was a big difference. Now the Idle was much better but still a bit harsh. I brought a friend over that is a professional hotrod builder. He could directly se what was wrong. The axel is not centered in the carb, thats why.
Im gonna change to edelbrock carb, manifold, new Cables, etc so in a week or two Im gonna take it to his garage

Thanks again for all help.

Regards Rob

No problem Rob.

An Edelbrock carb is a good choice and will solve all your issues. Plus they come with an electric choke so you will now have a properly operating choke. The Edelbrock carbs lack a little performance compared to most Holley's. But they are easy to adjust, reliable, and consistent. I like Holley's, but the Edelbrock's are excellent for driving and not having to tinker with it. The Edelbrock Thunder series carbs are the better line that they sell. They offer it in a 650 cfm size that would be suitable for an almost stock 351.

Did your friend suggest an intake manifold? Edelbrock's Performer RPM intake is a pretty good street intake. Although its a little taller than stock and sometimes the stock air cleaner won't fit under the hood.

Good luck, should be fun!

Best Regards,
Mike