Idle issues
Thread Starter
6th Gear
Joined: Jan 2020
Posts: 6
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Idle issues
I rebuilt my Carter AFB carburetor last night and got it put back on this morning. It idled perfectly when I initially started it up. I took it for a drive and it started to get very rough at idle and when I returned back to my garage, it would not idle at all. When I give it gas it stays running but as soon as I let off it stalls out. I did notice that the pcv valve was rusty on the inside and I tried to clean it up the best I could when I rebuilt the carb. Could this be a potential reason why the car will not idle? Any other thoughts would be very much appreciated.
Last edited by Seabeast; May 24, 2020 at 02:56 PM.
Safety Car
Joined: May 2014
Posts: 3,783
Likes: 655
It could be if the pintle inside the PCV valve is sticking open allowing excess air into the engine at idle.
Pull the rubber hose off and plug the end of the valve then start the engine to see if the idle is better. It may be a bit lower than normal but should not stall.
Pull the rubber hose off and plug the end of the valve then start the engine to see if the idle is better. It may be a bit lower than normal but should not stall.
Thread Starter
6th Gear
Joined: Jan 2020
Posts: 6
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Plugged the hose and no luck. The car still stalls out. When I rebuilt the carb everything was cleaned and only the gaskets were changed. I have made many adjustments to the idle mixture screws and it’s always the same result. Sounds like I may need to pull the carb back apart. Any other ideas of what to look for?
Le Mans Master
Joined: Feb 2008
Posts: 5,214
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From: NJ Hockey beer league
Exactly, what's the condition and age of your gas tank and fuel filter.
Last edited by Pilot Dan; May 24, 2020 at 08:05 PM.
Le Mans Master
Joined: Feb 2008
Posts: 5,214
Likes: 447
From: NJ Hockey beer league
Probably then a float issue. I'd remove the carb and re check the floats for debris and adjustment. Possibly a piece of trash from the rebuild that found it's way to one of the needle seats. Blow it out with compressed air and reassemble.
Race Director
Joined: Jan 2003
Posts: 17,659
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From: Central Arkansas
Might try removing the idle mixture screws and spraying carb cleaner with a straw back through the idle circuit to see if it might dislodge sone junk in it. If it does then the the carb and/or fuel line probably needs some more flushing.
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Le Mans Master
Joined: Nov 2015
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From: Really Central IL Illinois
Can you keep it running by choking it or squirting fuel into the primaries? This will help troubleshooting.
Do you have to choke it to get it to restart or pump the accelerator?
May have sucked a carb/manifold gasket due to loose installation torque or warped base plate creating a vacuum leak.
What was the reason for the rebuild?? How did it run before you did the rebuild?
Do you have to choke it to get it to restart or pump the accelerator?
May have sucked a carb/manifold gasket due to loose installation torque or warped base plate creating a vacuum leak.
What was the reason for the rebuild?? How did it run before you did the rebuild?
Thread Starter
6th Gear
Joined: Jan 2020
Posts: 6
Likes: 0
Thanks for all of the responses.
The car had been sitting for quite a while and actually ran really well before I started the rebuild. The carb was dirty externally and I figured while I had it pulled off the car for cleaning, I would just rebuild and make sure everything was clean and gaskets fresh.
After pulling the carb apart again, I noticed that the float drop was way too large (>1"). I have made the proper adjustments (23/32"). I have not had a chance to install the carb back on the car, but I would assume/hope this would solve my issues.
The car had been sitting for quite a while and actually ran really well before I started the rebuild. The carb was dirty externally and I figured while I had it pulled off the car for cleaning, I would just rebuild and make sure everything was clean and gaskets fresh.
After pulling the carb apart again, I noticed that the float drop was way too large (>1"). I have made the proper adjustments (23/32"). I have not had a chance to install the carb back on the car, but I would assume/hope this would solve my issues.
Last edited by Seabeast; May 25, 2020 at 11:48 AM.