Thread: Quadrajet won't idle

Try and see if it will idle with your hand partially over the top, causing less air/ enrichening it. have seen lots of Q-jets with internal airleaks in the idle circuit causing excessive leanness and weak and sometimes no idle fuel.

The airleaks are caused by overtightening the carb down to the manifold, distorting the top cover. This is made even worse on those equipped with a resin baseplate insulator.

The one I had on my WB 308 was so bad, I replaced it with a holley which was a far worse carb but at least it idled

The Q-jet is worth persevering with, IMHO they are a fantastic performance carb with good 'economy' if driven on the primaries.

JC

As justin said,try and restrict the airflow.You may also try getting a bottle or better still,a spray bottle full of water and spray around the carby,checking for any vacuum leaks and any vacuum hoses that haven't been plumbed.

Wayne

Idle adjustment screws all the way in?

Could be time for a kit. As stated, either idle circuit needs attention or you have an vacuum leak.
A gas analyser should give you a few answers as to the overall tune of it right throughout the rev range.

Incorrect or sticky float level also causes issues with these in much the same fashion as a Weber carb.

Cheers

Andrew.

Sounds like an air leak. Q-jets, in spite of their complexity, are almost trouble free. Most problems with them are human caused.

Originally Posted by Brian Hjelm

Sounds like an air leak. Q-jets, in spite of their complexity, are almost trouble free. Most problems with them are human caused.

I second that Q-Jet bloody good carby Much malined little understood.

Justinc rules,,
but I'm not sure I'd want my hand over the top of a carby thats known to backfire--

Originally Posted by Pedro_The_Swift

Justinc rules,,
but I'm not sure I'd want my hand over the top of a carby thats known to backfire--

Only put the hand over at idle Pedro! Just to prove the idle circuit leanout issue.

Oh, and according to my better half, I DON'T 'rule'

JC