Holley 715 Help

[s2ms]

The 3259 on my 66 started running rich in about the last 500-1000 miles or so. I pulled the carb and the secondary throttle plate bottoms and lower bores are covered in black, mostly dry soot on the plates. Primary plates and bores are clean and look great. I don't see anything obvious...float levels are good, no sticking or leaking floats, needles/seats look good, etc. The plugs are more fouled towards the front of the engine.

Could this be something as simple as a clogged air bleed? Any other ideas?

Thanks,
Dave

[tomhawk]

Would check pcv valve.   Run the engine in a dark garage with the hood up to check for plug wire arch. By your desc. the carb is okay. Could be vac. leak from carb gasket, or intake to head gaskets. Just some thoughts

[Drew Pojedinec]

Check timing and ignition as mentioned.
Fuel leakage is possible, but anything that causes bad combustion can make soot like that

[67350#1242]

Possible power valve leaking?