View single post by Bob 13902
 Posted: 06-25-2006 06:14 pm
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Bob 13902

 

Joined: 04-05-2006
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After rebuilding (Delta kits) both Stromberg carbs, and lots of follow-up troubleshooting, I can't seem to solve running rich at idle. Everything was rebuilt except replacement of needles and only 1 shaft seal was replaced on one carb. The engine is smooth and strong acceleration at above idle speeds, all the way to 7000 RPM. Sometimes at steady speed or deceleration, I feel slight surges. Moments after returning to idle, it begins to smoke terribly and the spark plugs become very black, sometimes fouling if sit at idle for extended periods. When the car is cold it needs no choke to start and stay running.

After rebuild, I had gas leakage and disassembled and reset floats, which essentially stopped all leaks except after running extended periods, I notice some gas seepage from the front carb choke...rechecked and lowered float more without seeing a change.  I did find a loose rear carb float support and peened it tight, but that didn't change anything. Lifting the piston results in an increase in speed; adjusted mixture 1 turn toward lean with no effect (had adjusted about 3 turns in an earlier iteration, with no effect, and reset to baseline before the 1 turn adjustment). I haven't re-checked the temp compensators (I set with hot air gun during rebuild), because I didn't think they could cause the problem I'm seeing. I assumed if not changing the shaft seals was a problem, it would make the engine run lean.

Any suggestions? Although the mixture needles had no obvious visual problem, could that be it? Is it likely that the new inlet valves are faulty - looked good. Floats seem to move freely, so it doesn't appear they are sticking. If I can't get success, anybody have a good suggestion where I can get some replacement carbs without problems?