Holley carb problems

[William P.]

I have a 71 LT-1 that I am having problems with the 4801 carb. It started hesitating upon acceleration so I rebuilt the carb, and now it runs very rich. (black smoke and won't idle) At full acceleration it runs fine, but at a crusing throttle position it bucks and I can see black smoke in the mirror. Any ideas?

Thanks in Advance
Bill Pearson
red/red 62
71 LT-1
#40831
pearwill@comcast.net

[Dave F.]

Re: Holley carb problems

Had the same problem with a Holley on a non-Corvette application. Major float adjustment is what you need to do.

[Jim T.]

Re: Holley carb problems

In rebuilding the carb did you replace the power valve? Running rich like you say I am thinking that the power valve is ruptured and not functioning.
Quick test. Remove the top of the air cleaner. Start the car. Now put a finger over the veritcal vent tube. If the car stumbles and dies replace the power valve. When you start your car and it backfires, there is a good chance that it will destroy the power valve. Newer Holleys have a anti-backfire protection with the use of a small ball bearing look alike piece. Holley power valves can be purchased individually at Auto Zone.