If it kept running after you shut it off the timming is to far behind try advancing it 5 degrees. Maybe 10.
Railguy

 

Eric,

I tried turning the curb idle screw counter clockwise but the idle didn't change.

 

Did you try putting pressure on the throttle to help it back? A vacuum leak would cause high idle. Also a common thing to do to holleys is drill a hole in the throttle butterflies to close them up bit if you drill the hole to big you can't get the butterflies closed enough to get it idled down. Are your butterflies drilled?
Railguy

 

Did you try disconnecting the throttle cable?

- Eric

 

Has it always run this way or did it just start . Because there an adjustment on the secondaries that could cause this but you have to remove the carb to get to it.
Railguy.

 

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There is also an idle advance adjustment on the chock . Which is on the opposite side as the throttle. This could be the problem too

Railguy

 

This is the adjustment on the secondaries it acts as a stop to keep the butterflies from closing to far and binding or sticking. If it is in to far it will hold the butterflies open a little .which would act like a vacuum leak. This is the adjustment that requires the removal of the carb so check the other one first . And try disconnecting the throttle cable as MDchanic suggested.
Railguy


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