Tillotson won't idle

Gary/IA

Gary/IA

Senior Member
I have blown out all the jets and passage ways. The top and bottom fit together good. The surface that mounts to the intake manifold is flat. I have installed new gaskets.

I have tried to adjust the idle but it just wont idle at a normal idle. If it idles at all(at a slower speed) if you speed the engine and let off the engine will die. I don't really notice much difference when adjusting the idle adj. screw. It does run great at road speeds.

I have several good carbs (zenith) but the car seems to run so good with this tillotson. I have run it two years and no problems. What am I missing? Any suggestions.
 
Gary/IA said:
I have blown out all the jets and passage ways. The top and bottom fit together good. The surface that mounts to the intake manifold is flat. I have installed new gaskets.

I have tried to adjust the idle but it just wont idle at a normal idle. If it idles at all(at a slower speed) if you speed the engine and let off the engine will die. I don't really notice much difference when adjusting the idle adj. screw. It does run great at road speeds.

I have several good carbs (zenith) but the car seems to run so good with this tillotson. I have run it two years and no problems. What am I missing? Any suggestions.
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The idle jet path is blocked, somewhere along the line but probably not the big tube called the idle jet.

The fix is what I call the carburetor Heimlich: Get the motor running somehow. Open the carb-side hood. Put a glove on your left hand (burn protection). Momentarily race the motor with your right hand on the throttle rod. Just as the rpm's peak, release the throttle rod and clap your hand over the carb air intake, momentarily completely shutting it off. Before the car can die, quickly pull your hand away. One treatment usually does the job, but sometime a few goes are necessary. With the engine at high rpm and the intake blocked there is tremendous suction all concentrated on the idle circuit. It WILL pull through anything that managed to get lodged in there.

Steve
 
Take a good look at the upper half.Somewhere in the middle of the neck is a little freeze plug.I have seen them fall out,for no apparent reason and create the exact symptoms you are describing. On the first one I saw it on I spent a long time trying to track down the cause of poor vacuum. I really wasn't familiar with Tillotsons and did not know about the plug.With the engine noise I never heard the hiss of the vacuum leak.I grabbed the carb for some reason and the car smoothed right out.I had covered the hole with my finger.It is an easy check.
 
Keith True said:
Take a good look at the upper half.Somewhere in the middle of the neck is a little freeze plug.I have seen them fall out,for no apparent reason and create the exact symptoms you are describing. On the first one I saw it on I spent a long time trying to track down the cause of poor vacuum. I really wasn't familiar with Tillotsons and did not know about the plug.With the engine noise I never heard the hiss of the vacuum leak.I grabbed the carb for some reason and the car smoothed right out.I had covered the hole with my finger.It is an easy check.
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Keith,
You hit the nail on the head! The little plug was missing. I covered the hole with my finger and was able to adjust the idle satisfactorily. I was all over that carburetor but looked right past that empty hole :o. I assume the vendors have the plugs and that they just press in.

Steve S,
Thanks for the hint on clearing the idle circuit.

Thanks for all replies.
 
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