Replacment Carb
Thread Starter
2nd Gear
Joined: Aug 2013
Posts: 2
Likes: 0
Replacment Carb
Hey all,
My wife has always wanted her own Corvette, seeing as I have one.
I bought her a pretty clean 1981 with 102000 on the clock. The engine was tired and smoked like a forest fire, so my buddy and I removed it and had it rebuilt at a local, reputable rebuilder. All went well until we fired it up. It runs but runs lean at idle and has a bad hesitation off the line. Adjustments and playing around with it has not helped much. Turns out some where along its life the carburetor was replaced with a rebuilt unit, numbers are wrong year and not from a Corvette. So I want to get rid of this electronic Q jet. Any recommendations for a replacement? I would like to have something that does not require much fabrication to install and is easy to adjust. Oh BTW the engine is a stock rebuild.
Thanks in advance for all the help.
Bob
My wife has always wanted her own Corvette, seeing as I have one.
I bought her a pretty clean 1981 with 102000 on the clock. The engine was tired and smoked like a forest fire, so my buddy and I removed it and had it rebuilt at a local, reputable rebuilder. All went well until we fired it up. It runs but runs lean at idle and has a bad hesitation off the line. Adjustments and playing around with it has not helped much. Turns out some where along its life the carburetor was replaced with a rebuilt unit, numbers are wrong year and not from a Corvette. So I want to get rid of this electronic Q jet. Any recommendations for a replacement? I would like to have something that does not require much fabrication to install and is easy to adjust. Oh BTW the engine is a stock rebuild.
Thanks in advance for all the help.
Bob
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
I would look for a bad vacuum leak now if it was running well earlier (not counting the smoking part). Vacuum lines, the carb base, the intake to head gasket, lots of places for a fresh engine to have a vacuum leak. Did you check the timing? That could be part of it.
Otherwise, I would try to find a correct carb for the engine and have it rebuilt properly. Search the forum for "Lars". He is reputed to havea carb service second to none. I hope to use his services soon myself.
Otherwise, I would try to find a correct carb for the engine and have it rebuilt properly. Search the forum for "Lars". He is reputed to havea carb service second to none. I hope to use his services soon myself.
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
I believe if you want to remove/disable the ECM you must replace both the dizzy and the carb. If you want a good off the shelf Q-Jet look at the "Jet Stage 1" if you left the motor stick, maybe stage 2 if you bumped up the power. Im sure there are folks with 81s will jump in with more input!
Good Luck!
Good Luck!
Racer
Joined: Feb 2012
Posts: 261
Likes: 3
From: Clawson Michigan
Ive been running a qjet from jegs for a few months with out any problems. It worked well right out of the box...but I did adjust the idle screws, choke and air valve per Lars papers
JEGS Performance Products#555-15800
JEGS Performance Products#555-15800
Last edited by Flyinace3; Aug 12, 2013 at 03:15 PM.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
a smarter man than me once said "90% of all carb problems are caused by the distributor' (sorry, lars, for the misquote). get the dissy set up first. if you narrow it down to the carb, rebuild it. you alraedy have a carb (although of unknown condition), so open it up and see what the previous rebuilders ahve done to it. if it hasn't been butchered, rebuild it. it may only cost $25 for a rebuid kit, and it's worth a try. i've rebuilt two qjets using lars papers, and both worked out very well.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The nuances of the 1-year-only 1981 induction and ignition systems has been discussed at length on this forum. You should be able to find all the info you need regarding your situaltion in Archives related to "1981 Carb Distributor". Do a search and see if that info will do the job for you. 
Thread Starter
2nd Gear
Joined: Aug 2013
Posts: 2
Likes: 0
Thanks for the quick response's.
My buddy is a tech, and a good one. He spec'ed out the timing and found the balancer had slipped so we replaced that. He also "dialed in the distributor" and made sure there are no vacuum leaks. He believes the carb is jetted (or tuned)for a smaller displacement engine. He says when you buy an off the shelf rebuilt you never know what your getting. He is basing this on "mixture dwell, oxygen sensor reaction and pattern, HC output and CO output. What ever all that means!!
I would simply like to get ride of the electronic carb.
My buddy is a tech, and a good one. He spec'ed out the timing and found the balancer had slipped so we replaced that. He also "dialed in the distributor" and made sure there are no vacuum leaks. He believes the carb is jetted (or tuned)for a smaller displacement engine. He says when you buy an off the shelf rebuilt you never know what your getting. He is basing this on "mixture dwell, oxygen sensor reaction and pattern, HC output and CO output. What ever all that means!!
I would simply like to get ride of the electronic carb.
