Hey,

I've got yet another question in my quest to tune a carb. I've got the car pulling pretty well now, but touching the throttle off of idle creates a lean surge which catches up immediately and pulls normal. I've played with the accelerator pump cam adjustment, but it hasn't taken care of the problem.

Any ideas?

 

Does the shot come on immediately when you start to open the throttle? If not, the accelerator pump may just need to be adjusted.

Does the lean spot happen when you slowly open the throttle, or only when you open it quickly? If the former, you need a higher number power valve. If the latter, then it might be an accelerator pump problem.

 

Well, I just put a 9.5 in it. It helped alot, but I still get the surge some times. It's worse if I apply atleast 1/4 throttle from idle. I can slowly edge the throttle on without making it happen. And if I don't stall it up high enough when I launch then it will bog as well.

 

More than half the time, "carb problems" are not carb problems, but timing issue.

 

But wouldn't that cause problems at any throttle amount? I've set the timing with a light, so I don't think it's timing related.

 

Timing varies w/ rpms so no. Did you set the timing at idle and WOT? Have you recurved the distributor advance? Are you running vac advance?

 

I set it at idle. Vac advance, haven't recurved anything cause I just bought the distributor from Jegs. It's their Street/Strip Dist. So I'm not sure what the total timing is on it.

 

Did you set the timing with the vacuum advance disconnected?

 

If you don't know what total timing is, and when it is coming in, you don't really know what the engine is doing. That should be the first thing you check. It will probably be all in by 2500-3000 with an aftermarket performance dist.