I have a Motorcraft 2100 on top of a '73 400, and 9 months out of the year she is great, but with these cold wintry nights right now I am having trouble with lean bogging\backfiring, off-idle hesitation and stalling until she's fully warm. I've nailed it down to the accelerator pump; it works fine but I am aware that it can be adjusted to provide a larger shot of fuel each sweep and was looking for some tips as to how to do that. I believe there are 4 holes on the accelerator pump lever and the rod is in the third one, if I recall correctly. Not really sure which hole makes it "richer", or if there are any other adjustments. Any help is appreciated.

 

I would check the choke system and make sure the air valve setting at choke is correct. If the air valve is not set properly it can starve the engine for air which can cause the engine to run rich or it can also cause a lean out condition, either of which will cause the engine to backfire, bog down, etc. . Choke adjustments, fast idle speed, air valve adjustment, choke unloader, etc., are critical for the system to work properly year round. My guess is that your problem isn't accelerator pump related but, for the most fuel shot, place the rod in the hole at the end of the accelerator pump lever.

John

 

Moved the rod up a spot to the fourth hole; seems to have done it. Choke was never the problem, as the issue would arise for the first couple minutes after the choke opened, no matter how rich the setting.

Thanks!