Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: canadian nascar on September 23, 2009, 05:45:50 PM

Title: midrange lean
Post by: canadian nascar on September 23, 2009, 05:45:50 PM

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

Title: Re: midrange lean
Post by: Cliff Ruggles on September 24, 2009, 03:36:38 AM

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

Title: Re: midrange lean
Post by: canadian nascar on September 24, 2009, 06:22:58 AM

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

Title: Re: midrange lean
Post by: Cliff Ruggles on September 28, 2009, 04:08:54 AM

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

Title: Re: midrange lean
Post by: canadian nascar on September 28, 2009, 04:55:01 PM

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

Title: Re: midrange lean
Post by: Cliff Ruggles on September 30, 2009, 04:30:32 AM

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