Have you recently replaced the fuel pump? Most of the pumps you buy now have way too much pressure. The high pressure overwhelms the needle / seat assemblies and causes it to flood.
Trouble shoot it and let us know:
With engine running at normal operating temperature and air cleaner removed:
when it begins to lose rpm, choke it without moving the throttle by manually closing the butterfly. If you can't choke it with the butterfly, use a shop towel or your hands to close off most of the primary air horn opening.
If it picks up rpm when you choke it, you are idling lean. Could be:
Fuel pump going bad - check pressure and volume at idle.
Float level low. Check adjust float. Check for bad float.
Idle air adjustments needed. Set with a vacuum gauge is recommended.
Throttle blades sticking and slowly closing.
If the engine loses more rpm quickly when being slowly choked, Could be:
Float level too high. running rich - flooding.
Bad float or float adjustment.
blown power valve.
too much fuel pressure lifting needle off of the seat.
If you have a Holley, go to their site for a little help.
What kind of vacuum do you have? My 302 has the same issue but not in stock trim. It has done it with stock fuel pump and now with in tank pump with bypass regulator and same with multiple carbs. I only have 7-8 vacuum and it is a happy camper at 900 to 100 rpm but around 800 it will idle fine for a while the kind of taper off and die. I tend to think low vacuum is the issue.
Check the gas cap, fuel tank for correct venting. If it isn't venting correctly, the fuel flow to the pump and carb will be altered, and could possibly do what you describe.
What idle speed is it set at? Like Scott's 302, mine is happy at 900 and up. Is your idle speed set too low?
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Team Camaro Tech
2.4M posts
82.9K members
Since 1998
A forum community dedicated to 1st generation Chevy Camaros owners and enthusiasts. Come join the discussion about performance, builds, restoration, modifications, classifieds, troubleshooting, reviews, and more!