Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Diagnose a Quadrajet carburetor problem => Topic started by: 68goatie on September 06, 2010, 01:28:24 PM

Title: Poor running when Hot
Post by: 68goatie on September 06, 2010, 01:28:24 PM

Is anybody else having problems with poor idle and performance after vehicle gets hot (85 deg. day)?  I've tried multiple fuels- added a elec. fuel pump straight to carb- re-routed fuel lines away from engine-The vehicle in discussion is 1968 GTO- 400 with 068 cam and headers- Auto- Q-jet-  Vehicle runs fairly good when you pull it straight from garage and go- after one hard run it begins- Suggestions?

Title: Re: Poor running when Hot
Post by: Schurkey on September 06, 2010, 03:14:14 PM

Have you adjusted the idle mixture screws with the engine HOT?

Title: Re: Poor running when Hot
Post by: 68goatie on September 06, 2010, 03:27:19 PM

Yes- It acts like it's vapor locking- Mixture screws really have no effect- Also the high rpm/high load side of it suffers alot- spits and sputters/lean pop- Just wondering if the fuel today is making that much of a diff- have not tried a race fuel yet- Starts right up though?

Title: Re: Poor running when Hot
Post by: Toronado on November 11, 2010, 06:23:27 PM

no way to fix it, unless
you take it apart, you
most likley have the float
thats brass or the level
is set wrong. It has to be set up
from the inside out not the other way around.