Pontiac Lemans

1966 Pontiac Lemans Fuel System   

My 1966 pontiac lemans stalls or hesitates when I try to abruptly accelerate when standing still. It starts instantly when temps are 75 degrees or less, but in warmer temps it takes 3 or 4 seconds to start. It has the factory 2 barrel Rochester which has been rebuilt twice. It is a California car with the air pump/emissions gadgets removed. 326 engine. Runs great otherwise. Can you help?

I'm wondering if you have spark during the brief no-start period. Or if perhaps there's to much fuel, try holding the accelerator to the floor when above 75, does the engine start more quickly?

Have you checked spark advance?

I am aware of a vacuum advance but not a spark advance. Where is it, and how do I check it?
As for the pedal to the floor over 75 degrees, I'll try that and let you know.
I read about an identical problem with the identical car on your website. Do 1966 California cars share this tendency. I contacted the original owner and he said the car was hard starting from day one. The carb and manifold are different on California cars.

Hard starting on hot days?

Vacuum advance for spark control (same). You can check for functionality with a timing light, but accuracy is a little different.

How do I check the function with a timing light? I set the timing recently and it is right on. Also, do you mean that the vacuum advance is the same thing as the spark advance?
I tried to find a new vacuum advance when I rebuilt the car, but nobody sells them. Do you know of a source?

Simply rev the engine while observing the timing marks with a light, does the timing change?