QJet Help!
Thread Starter
Intermediate
Joined: Jan 2006
Posts: 42
Likes: 0
From: Fisherville, KY
QJet Help!
I rebuilt my perfectly running carb over the winter and now it will not run correctly. I rebuilt it because it leaked fuel out of the bowl overnight. It is a 78 PACE car on a L-82, 4 speed. Carb number is 17058211. Here is what it does. It surges back and forth between 1500 and 3500 RPMs without touching the gas pedal. It will even run with the idle mixture screws, screwed all the way in. I can cup my hand over the air inlet and cause the engine to run smooth however it speeds up considerable.
What do I need to do?
John
What do I need to do?
John
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
It could be any number of things. One that comes to mind is you may have used an incorrect gasket. If the bowl leaked out, did you find the leak (well plugs, porous casting) and fix it?
God bless, Sensei
God bless, Sensei
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The original leaky carb could indicate a crack in a casting or some other defective part in the carb. Rebuilding it in either case would not fix that kind of problem. The carb castings need to be checked for leak paths before a rebuild can be justified.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
Look for a vacuum leak. When you cup your hand over the carb you are richening the mixture.
Since it idles up when you do that, we can be pretty sure its running lean.
Also, a large vacuum leak can behave like the throttle baldes are open more than they are, causing your high idle.
Since it idles up when you do that, we can be pretty sure its running lean.
Also, a large vacuum leak can behave like the throttle baldes are open more than they are, causing your high idle.
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
Look for a vacuum leak. When you cup your hand over the carb you are richening the mixture.
Since it idles up when you do that, we can be pretty sure its running lean.
Also, a large vacuum leak can behave like the throttle baldes are open more than they are, causing your high idle.
Since it idles up when you do that, we can be pretty sure its running lean.
Also, a large vacuum leak can behave like the throttle baldes are open more than they are, causing your high idle.
God bless, Sensei
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Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
The carb should be assembled with the gaskets DRY!. It looks like you used RTV, which is gasoline soluble. GET RID OF IT NOW BEFORE IT GUMS UP YOUR ENGINE! If you used that on the other gaskets, it probably has gotten somewhere it should not be and is causing your problems.God bless, Sensei
Intermediate
Joined: Nov 2006
Posts: 29
Likes: 0
Yes, install a dry gasket. I have the same type on my 1980. Remember to torque the bolts properly too. Mine doesn't leak and I torqued them in this sequence:
first pass....5 ft lbs
second pass....10 ft lbs
final pass....12 ft lbs
first pass....5 ft lbs
second pass....10 ft lbs
final pass....12 ft lbs