RATT7

Finally resolved the off idle stumble on my 1980 - I first checked the ignition system and replaced the cap, rotor, plug wires and plugs. I checked the emissions and emission hoses and this was up to spec. Lars paper indicated how to disable the linkage for the accel pump and upon doing this and then reving the engine there was not change at all in performance. According to Lars the problem seemed to point to the accel pump. I removed the top of the carb last week and determined that the accel pump took alot of effort to remove from the carb, as per Lars paper he mentioned that Alcohol and additives in todays gas will cause the rubber pump cup on the accel pump to swell and this is exactly what happened. I would never have guessed this because the rubber cup was not cracked or distored, but when compared to a new ruber cup that I installed you could see a difference in size. The car is running fine now when I drop it in gear - Would never have thought of a swelled pump cup as the problem - Thanks Lars for your suggestion on the Q q jet paper

Black'69

Lars is the man! Sent my carb to him for a rebuild a couple of months back, runs like a bat out of hell. :cheers:

Shark Racer

How much is involved in the accelerator pump rebuild? I'm starting to think this may be my problem as well...

-Steve

Stewart's74

Its easy, pop the top off the carb and swap out the accel pump. Lars sent me step by step directions. It really took the mystery out of carb repair :thumbs: