1979 Chevy Luv rough idle after warmed up

Old 10-01-11, 11:53 AM
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1979 Chevy Luv rough idle after warmed up

Hey guys I have a 79 Chevy Luv that I am trying to get smoothed out at idle, when its cold the idle is great, when its warm the idle is quite fast (1100 - 1300 rpm) and if I back off the idle speed ajustment screw it dies right out. The choke is opening on time, the secondary butterfly is closed down and I can see fuel running into the carb from the primary jet (which seems odd). I have rebuilt the carb, it used to not idle at all, and when I did I checked everything out, all seemed to be in good shape. Running down the road the truck is great, very smooth and of you mash it you can feel the secondary pop open for the extra airflow. Any suggestions would be useful, a description of operation of the carb would be WONDERFUL!
Old 10-01-11, 12:19 PM
the_tow_guy's Avatar
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Vacuum leak comes to mind; might want to double check all vacuum lines, fittings, carb attachment, etc.

Haven't worked on a carbureted vehicle (other than the lawnmower ) for quite a while.
Old 10-01-11, 06:49 PM
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hah, got a keeper, hah? I'd start with carb to plenum gasket. when you get new one, put some high temp sealant on it. be careful with corner bolts and ears on carb. I broke those ears off very easily, and bolts strip aluminum cut threads very easy too. hey, start with re-tightening those bolts (gently) and see what happens.

do brake fluid spray thing. should point where leak is.

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