Carburator problems Need help.
Thread Starter
Racer
Joined: May 2005
Posts: 306
Likes: 0
From: Annandale Va
Carburator problems Need help.
Just installed new Hooker Headers and sidepipes. I start the car up and starts fine. Warms up idels about 750 to 800rpms. Drive it for a short time, couple of miles up to store runs great. Leave head back home about halfway home notice it's ideling about 1500 to 2000. Rev it a couple of time to see if it will drop back but no luck. Then when I pull into drive and shut it off a half second later pretty good backfires out of pipes.
Engine is 350 with Edelbrock manifold and Carburator.
Any suggestion of where to start tweaking to rid this.
Thanks in advance for any help.
Engine is 350 with Edelbrock manifold and Carburator.
Any suggestion of where to start tweaking to rid this.
Thanks in advance for any help.
to the top. 
Burning Brakes
Joined: Jul 2005
Posts: 787
Likes: 0
Are you saying it idles at 700-800 and later at 1500, both when it's fully warmed up?
If so, I would wonder if the mechanical advance is sticking....and check the timing at various rpms. The original HEI dizzy in my 75 had worn pivot holes and generally the mechanical advance was sticky. I still have it tucked away for originality, but will have to rebuild it.
If the timing/advance acts like it should, I would reset the idle speed once the engine is idling as high as it gets.....may make warmup a pita, as it frequently is on old cars, but thats the way I'd go.
If so, I would wonder if the mechanical advance is sticking....and check the timing at various rpms. The original HEI dizzy in my 75 had worn pivot holes and generally the mechanical advance was sticky. I still have it tucked away for originality, but will have to rebuild it.
If the timing/advance acts like it should, I would reset the idle speed once the engine is idling as high as it gets.....may make warmup a pita, as it frequently is on old cars, but thats the way I'd go.
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Did the engine function correctly prior to the exhaust mods?
Fuel Related Possibilities:
-Fuel mixture may require adjustment following installation of headers/sidepipes.
-Carburetor float/valve assembly may need attention.
-Vacuum leak.
-Vacuum leak that only appears while engine is at operating temp.
Ignition Related Possibilities:
-Mechanical advance weights not fully retracting at idle.
-Unwanted vacuum supplied the vacuum advance canister at idle.
Fuel Related Possibilities:
-Fuel mixture may require adjustment following installation of headers/sidepipes.
-Carburetor float/valve assembly may need attention.
-Vacuum leak.
-Vacuum leak that only appears while engine is at operating temp.
Ignition Related Possibilities:
-Mechanical advance weights not fully retracting at idle.
-Unwanted vacuum supplied the vacuum advance canister at idle.
