single barrel carb problems

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snowcrow

snowcrow

2 Time dart owner
Joined
Apr 23, 2012
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Sanpete, Utah
So I had a fellow mechanic go through and rebuild my carburetor on my '76 slant. He tuned it a bit so it would idle higher when I start the motor which was fine with me since the motor seemed to want to die during idle anyway. Well I thought he fixed the problem but the carb seems to be suffocating itself with an issue to where when I throttle the "choke plate" (not sure the proper term) that the gas pedal cable adjustable screw rests on to keep idle, moves out of the way and when the adjustable screw comes back down when I let off the gas, it'll almost die when the car is at a stop when idle. I played around with the plate and the car will idle great when I get that screw back onto that "choke plate" but it wont stay on it. Any ideas? I'd be happy to answer any other questions to make more sense of this if I'm unclear with anything, just need help and I think I may be flooding the motor when having the issue cause of wet looking spots near gaskets.
 
When you say 'choke plate', do you mean the jagged or stepped looking piece of metal that rotates on the side of the carb and that one of the idle screws rests upon? If so, that is the fast idle cam. There is a screw that rests on the 'steps' of that cam that adjusts the idle speed when the choke is active during engine warm-up; this is the 'fast idle screw' that it seems you have found.

When the engine is fully warmed up, that cam flips totally out of the way, which it sounds like it is doing. At this point, the car's idle is set by a different adjustment screw, called the idle screw, that rests against a non-moving part of the carb somewhere, and does not come to rest on the fast idle cam. It sounds like you need to find that idle screw and adjust that, it shoudl be nearby the fast idle screw.

Can you post a pix of the fast idle screw area? Or do you know if you carb is a Holley or a Carter?
 
I'm Pretty sure it's the Holley carb and yeah that notched plate. Sounds like it's doing its job to me to!
 
So we can assume that issue is fixed?

I would expect your carb is a model 1945 or 1920 if a Holley; you can look those up to find diagrams of where the idle speed screw is located relative to the fast idle screw.
 
Officially saying a huge thanks to nm9stheham for the info that got me doing my own research. Turns out I just needed to turn in a screw like 3 turns to bring the idle up! Were all good now!!
 
Snowcrow, do you have a tach to determine just how fast you're making this thing idle just to run? If you are going over 1k rpm just to keep it from dying then you may be chasing a vacuum leak.
 
It sounds to me like your choke is not adjusted properly. It's "pulling off" too soon. Adjust it a little richer in steps to see how it improves.
 
There is indeed an amazing amount of stuff out on the internet.... you just need to filter it a bit.

Snowcrow, I assume that you used the video to find that separate idle screw for regular idle adjustment? Just curious... glad it is better now!
 
Also, get a manual - factory or Haynes. They all detail adjusting idle speed and other important settings and maintenance.
 
no tach but sounds like i should get one serj22! and to nm9stheham, yeah i watched like 50 seconds of the video then went out to play! haha
 
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