midrange lean

[canadian nascar]

hi Cliff,
i have a modified 81 turbo trans am and i have a lean during half throttle at 2500rpm should i be looking to at more fuel ? how could i do this? or should i be looking to change something on my distributor.

i bought a pair of richer secondary rods from you in july and you told me about the apt.

thankyou kevin

[Cliff Ruggles]

When you describe "half throttle", are you on the primary side of the carburetor only?....Cliff

[canadian nascar]

i would guess yes, i am new with carbs. i put the throttle down half way as i am driving. and i can tell when the four barrels come on, with a bit more throttle and then it is fine

kevin

[Cliff Ruggles]

If it is lean at "heavy" part throttle, the jet size will need increased to richen it up some.....Cliff

[canadian nascar]

hi Cliff,

i don't think i was clear, i would say that i am still in the primaries when this happens then if i put it down all the way the lean goes away. would this still mean to change the main jets?

kevin

[Cliff Ruggles]

If you have a lean condition on the primaries only, determine if it is at heavy throtte, or light throttle, or both.

If both, go one size larger with the jets.

If light throttle only, raise the metering rods via the APT, and/or go to metering rods with a smaller second section.....Cliff