General Category > Quadrajet Carb Talk and Tips

Early non APT primary rod set up.

<< < (2/2)

Pav8427:
Thats a new one on me. Would assume that would work for any non APT early units.
Will keep that one in my toolbox as I move forward.

Thanks. Doug

jim71400:
I think you can knock out a plug in front of base/throttle plate  and there is screw in there which is an early style of APT adjustment????? Dont think it needs packing??? Could be wrong.

Kenth:
There is no APT on Pontiac Qjets until the 1975 M4 units, however there is an conical off-idle adjustment screw under the triangular washer on air-horn wich affects the upper idle circuit air-bleeds on 1969 and earlier units and affects the upper main circuit on 1970-74 units.
Changing rods (non-B suffix) and/or jets is the way to tune a Pontiac Quadrajet if needed.
I have found this is seldom needed if the idle circuit is properly modified for todays fuels.
Also, changing main jets/rods will NOT help the idle circuit as the idle circuit is a stand alone circuit with its own jets and airbleeds.

HTH

Cliff Ruggles:
Correct, jets and metering rod are NOT the correct way to tune the idle system.  Even so I see folks trying to do this.  Just yesterday I took a call from a guy who was clear down to .064" main jets with 44B rods trying to cut-off some idle fuel because his A/F meter showed WAY rich at idle. 

I told him that he needed to look at IFR's and DCR's, plus the IAB's, and that I couldn't help without a carburetor part number or specifics on those items.  I got neither one so moved on to better things......FWIW....

Navigation

[0] Message Index

[*] Previous page