I just put my new carb on my 69 GT500 that was purchased through Pony Carbs. It started right up but I had problems with the idle running to high. It seemed like the dashpot (would return to idle if throttle linkage was pushed forward). After I played with the timing (no light used, as they recomend), dashpot and idle screw all seemed well. I just got back from a 170 mile drive, the temp never ran high, no ping, but now I have pre-ignition when turned off, I have not tried it cold. I never had that prior. I have read that it is more of a temp problem (engine was never extrordinarily hot). I still need to replace the choke return hose (I left it open to air today). Could it still be the timing or could the lack of choke return (the forward vacuum on the carb) cause this issue? Thanks, Darryl
Re: Pre-ignition Make sure you set the idle in park and drive to what the book calls for and i would check your timing with a light . Remember that dwell affects timing and make sure that your vacuum advance is not binding. Mike
If you are talking about the engine trying to run after the key is switched off, that is a function of air getting into the engine. Whether it's a vacuum leak, or the throttle plate stop set too high, your problem can be solved by making sure there are no vacuum leaks and setting the idle to the low end of factory specs. Before the manufacturers did away with carburetors on late model cars, they had a solenoid that was the throttle stop when the engine was running. When the key was switched off, the solenoid de-energized and closed the throttle plates completely. The engine can not continue to try to run with no air. Another trick to use temporarly is to turn off the engine while it's still in drive, then put the shifter in park. Good Luck Bill
