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chevrolet 02-08-2024 04:26 PM

Q-jet problem
 
Have an 85 chevy 1 ton pickup with 454 and the q jet runs good but,,, it's always ben rich on idle .It will drive you out of the shop. Had the truck since new just never messed with it because dont know enough about them as far as rejecting them plus it runs good with it. Any one know of someplace I could get help with this thing. Its all stock.Ive rebuilt it a couple of times and done the little things I do know.Thanks Much...DR.

corky 02-09-2024 12:27 PM

Re: Q-jet problem
 
Find an old carb man and have the chock checked.

Mark Yacavone 02-10-2024 09:26 PM

Re: Q-jet problem
 
You removed the idle mixture screw seals, right?

Terry Cain 02-11-2024 06:12 AM

Re: Q-jet problem
 
fuel leaking out jet well plugs.

Mark Yacavone 02-11-2024 02:23 PM

Re: Q-jet problem
 
Quote:

Originally Posted by Terry Cain (Post 693319)
fuel leaking out jet well plugs.

That stopped in the late 60's with a different process to install and seal the plugs.

REGGIE WINKLES 02-24-2024 12:11 PM

Re: Q-jet problem
 
Mark is correct about the base plugs. The later Rochester Q-Jets don’t leak. Try leaning with it with the mixture screws. Also check for a “sunk” float.

monte385 03-08-2024 03:20 PM

Re: Q-jet problem
 
Are you sure it's rich & not lean? Eye burning is lean, if not just gassy could be rich.

Henrys Toy 03-10-2024 09:33 AM

Re: Q-jet problem
 
Quote:

Originally Posted by chevrolet (Post 693100)
Have an 85 chevy 1 ton pickup with 454 and the q jet runs good but,,, it's always ben rich on idle .It will drive you out of the shop. Had the truck since new just never messed with it because dont know enough about them as far as rejecting them plus it runs good with it. Any one know of someplace I could get help with this thing. Its all stock.Ive rebuilt it a couple of times and done the little things I do know.Thanks Much...DR.

Good morning to all,
Maybe you just need to lean the Primary metering rods one or two numbers.
I'm sure the carb can't be that far off metering wise if you've owned this vehicle and someone else didn't get inside and "Fix " something? I'd get it apart and look at the number stamped on the rod, if it's a 41 try a 42 or 43 primary rod.
Does that carb have an Adjustable Part Throttle screw? You can try turning the screw clock wise in small increments and then drive the truck. You might want to check your ignition timing and get a vacuum gauge on this also and monitor what's going.
You've got a couple of things to look at, best of luck on your adventure.

Respectfully,
Henry Kunz 1534 H/SA

Mark Ruset 03-10-2024 03:03 PM

Re: Q-jet problem
 
Quote:

Originally Posted by chevrolet (Post 693100)
Have an 85 chevy 1 ton pickup with 454 and the q jet runs good but,,, it's always ben rich on idle .It will drive you out of the shop. Had the truck since new just never messed with it because dont know enough about them as far as rejecting them plus it runs good with it. Any one know of someplace I could get help with this thing. Its all stock.Ive rebuilt it a couple of times and done the little things I do know.Thanks Much...DR.

It may be possible since you mentioned that the carb has been rebuilt a few times that the overhaul kit used may be incorrect. i would start with a new quality overhaul kit specifically. Designed for your year make and model. Try and locate a Delco overhaul kit. I had good luck using Quadrajetparts.com for all parts and gaskets.

monte385 03-10-2024 03:24 PM

Re: Q-jet problem
 
Cliff has good parts too.

Mark Yacavone 03-11-2024 10:39 PM

Re: Q-jet problem
 
I had an 88 P 30 chassis m/h that came with the 86 Q jet engine.
Had dual air pumps but no cat/cons.
It was very lean from the factory. I had to richen it up to pull a trailer up a hill.
Problem then was, I had to lean it out every year for the E-check money grab.
My point here is it could be lean if all original .But being apart at least twice..no telling. That's why i asked about the idle caps.
I agree. Start all over with the right kit and some research as to what it came with.
Good luck , Mr louis chevrolet, if you ever return

StarRacing 10-04-2024 10:37 AM

Re: Q-jet problem
 
That?s a sweet truck you?ve got! If it?s running rich at idle, it might be worth checking the float level or adjusting those idle mixture screws. I?ve had a similar issue with an old pickup, and sometimes a vacuum leak can also mess with the mixture. If you haven?t already, a good tune-up could help too. You might also want to connect with a local car club or find a classic car forum; there are usually folks who love helping out with these kinds of issues.


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