Does it have 13:1 or does it have 14:1 at idle?
Is your leg broken or is it not? We can only diagnose what you write us in reading. The bigger the number the leaner the condition, 13: 1 is not too bad where 14 is bad and probably needs a computer to make the car live with that much leanness at idle-certainly some heated air to the carb. How quickly do these sensors react? On these cars where smog is a not a concern , you can always err on the rich side without a problem.

The primary function of an accellerator pump is to add additional gas when the throttle is opened suddenly-when there is'nt enough gas momentarily being drawn out of the float bowl (sudden lack of vacuum due to throttle blades being popped open). I think in this situation, the acellerator pump will be used as a crutch to cover up a faulty (dirty or clogged) off-idle or transision passages which are used to ease the fuel into the main metering circuits.

That is what they were designed for, and this is what you dont have. I feel something is preventing fuel passage thru them, loosely and commonly termed dirt. Obviously the main circuit is clear as you have no prob holding say 3000 rpm, and no prob holding say 600 rpm- so no trash in the idle circuit, but a big stumble(does it pop thru the carb?) when you try to take off. What happens if you ease into throttle vs. jumping into it? Jumping into it need the pump for help, easing into it need an operating transition circuit. What is your timing at idle? and do you have an operating vacuum advance?

"Back in the old days" when today's folks chuckle and think things were not pertinate to today's probs, a guy who was working with the same problems on his 270 hp two-four bbl '57 chevy and trying to check it out would have singed eyebrows from leaning over the carb (a bump on the back of his head from the hood)and a burnt spot on his hood all from staring down a backfiring carb (or two). Be careful looking down a loaded gun or carb. Very lean mixtures go "pop" thru the carbs.

Last edited by preacher-no choir; 12/13/11 09:57 AM.