Stumbling carb?
Thread Starter
Drifting
Joined: Jan 2002
Posts: 1,411
Likes: 0
From: Dandridge TN
Stumbling carb?
Just got my cam broke in yesterday and didn't pay much attention to the carb. I noticed that running it at 2200 rpm's while breaking the cam in it was smooth. When I let it get below 1000 rpm's it wanted to die, and when I tried to keep it running it didn't want to react, it would stumble and stall. As long as I stayed above 1500 it was smooth. Sounds like a vaccum leak somewhere what do you guys think? I rebuilt the carb myself and everything went back as normal. The instruction sheet in the carb rebuild kit showed a little ball that went down inside of the jets that spray fuel into the carb, my carb didn't have one of these. It's a Holley 650 square bore sitting on a Eldelbrock performer intake. Any advice on this?
5th Gear
Joined: Dec 2001
Posts: 5
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From: Ontario
Re: Stumbling carb? (Steve Adkins)
Sorry I don't have an answer for you. But since I'm suffering similar symptoms, I don't mind moving this up for you.
My car also stalls below 1500 (vacuum just under 20 in. when starting and drops to 10-12 at 2500 rpm) I thought vacuum at first as well.
I'm contemplating rebuilding the carb to try to fix this. The carb was fine prior to winter storage.
Does anyone have suggestions? Thanks in advance.
My car also stalls below 1500 (vacuum just under 20 in. when starting and drops to 10-12 at 2500 rpm) I thought vacuum at first as well.
I'm contemplating rebuilding the carb to try to fix this. The carb was fine prior to winter storage.
Does anyone have suggestions? Thanks in advance.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Re: Stumbling carb? (Steve Adkins)
It is usually caused by being too lean.
If you can find a vacuum leak, that'd help
check your idle screws
Put your hand over the carb to choke it a little, if that hels it IS lean.
BTW I had a carb once that got worse every time I cleaned it, I finally brought it to work and cleaned it in a hot ultrasonic vapor degreaser, it cleaned every bit or oil and dirt off of it.
The thing ran like poopie!
Turns out the bores for the butterfly pivot rods were worn and causing a vacuum leak!
I bought a new carb and it never ran better :D
If you can find a vacuum leak, that'd help
check your idle screws
Put your hand over the carb to choke it a little, if that hels it IS lean.
BTW I had a carb once that got worse every time I cleaned it, I finally brought it to work and cleaned it in a hot ultrasonic vapor degreaser, it cleaned every bit or oil and dirt off of it.
The thing ran like poopie!
Turns out the bores for the butterfly pivot rods were worn and causing a vacuum leak!
I bought a new carb and it never ran better :D
Thread Starter
Drifting
Joined: Jan 2002
Posts: 1,411
Likes: 0
From: Dandridge TN
Re: Stumbling carb? (427V8)
Keith, I did put my hand over the top of the carb and it stalled out right away, but I noticed it had alot of vacuum pulling on the palm of my hand hard. My idle screws are turned out 2-1/2 turns each. Maybe I should adjust them. What do you think?
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Re: Stumbling carb? (Steve Adkins)
Did you cover the carb completely? Or just cover part of the carb?
The idea is to restrict the airflow, but not to completely suffocate the car:D
I usually put the side og my hand on the choke horn with the hand straight up, pinky on the bottom, then slowly rotate the hand ofer the carb. As you get to about 45' you are starting to chke the car a little. The car will either start to slow down or speed up as you slowly choke it. If it speeds up it is running better choked which means it needs more fuel. If it slows down it's rich enough...
The idea is to restrict the airflow, but not to completely suffocate the car:D
I usually put the side og my hand on the choke horn with the hand straight up, pinky on the bottom, then slowly rotate the hand ofer the carb. As you get to about 45' you are starting to chke the car a little. The car will either start to slow down or speed up as you slowly choke it. If it speeds up it is running better choked which means it needs more fuel. If it slows down it's rich enough...
Drifting
Joined: Nov 2000
Posts: 1,361
Likes: 0
From: Honolulu Hawaii
Re: Stumbling carb? (Steve Adkins)
Before you start messing with the carb, make sure your timing is set correctly. If your timing is set too retarded, you'll encounter that idle problem. You probably have it set to approximately 10-12 deg initial already, but I just wanted to make sure that that wasn't the issue. Good luck!
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