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Author Topic:   Carburator
hms
Dirt Roller

Total posts: 16
posted May 03, 2004 08:40 AM  
I need help Sat. 17 laps into the feature my car started loading up I speed up on the yellow and it cleared up then it wouldnot idle down it was on a fast idle. Sunday I was trying to figure it out and all I could get it to do was start and die. My fuel pressure is at 8.5 I run alcohol I visual inspected the powervalves and they look alright any ideas will be very appreciated.

Dman
Dirt Freak

Total posts: 270
posted May 03, 2004 08:56 AM  
Sounds like the secondaries are not shutting down (sticking open slightly). Do you run a belt drive pump? Do you have a regulator? Pressure at idle should be around 3 pounds and 8 to 9 lbs above 4000 RPM.Stainless needle and seats have a problem sealing some times and occasional flooding will occur.Check and replace them regularly.The stainless needle will hammer the seat away and not make a good seal after time.Also if you are running brass floats make sure they have not deformed from a backfire through the carb.This is very common.Check that the float moves freely all the way down and up.
If that all looks good check for a bad base plate to body gasket in the carb.They have been known to shrink up and deform causing vacuum leaks.Good Luck! Dman

mod70
unregistered Total posts: 270
posted May 03, 2004 02:10 PM           send a private message to Dman   Edit/Delete Message   Reply w/QuoteBBBBBB
I had a bad base plate last year that wouldn't let me idle below about 1500 RPM. The thing was warped brand new from Holley out of the box. It wasn't more than 1/16 in. but it was enough to cause a vaccum leak. Start 'er up and spray brake cleaner around the base and listen for the engine to bog down. When it does, you've found the leak. I took a belt sander with 150 grit to mine to get it level, checking it with a good straight edge as I went. Good luck!

MOD75D
Dirt Freak

Total posts: 236
posted May 03, 2004 04:37 PM  
I agree with 70 sounds like a vac. leak. I had this happen to me and found a little crack in one of my vac. port plugs. It would run but not Idol and if you rev it up after turning in the screw to make it idol it would still die. Found plug replaced it and problem was gone. Hope this helps.

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