OK, here goes - I bought a B a few months back that runs sweet as a sewing machine. At more than 1/2 throttle it had fuel starvation problems. OK, fuel blockage somewhere - and the carb leaks when the engine is not running.
So I replaced the sediment bowl assembly and fuel line (lots of rust flakes in the old sediment bowl inlet), rinsed out the gas tank, and replaced the carb float, needle valve, and seat. I re-used the carb body gasket since I didn't have one - had a few small internal tears but nothing to write home about.
Reassembled it and presto! no carb leaks. Cranked it up and wow! 1/2 to full throttle it ran great. Below half throttle it was waaay too rich, smoking and so forth. Well, that must be a blockage in the air mixture screw. So I removed the screw, blew in so compressed air (air came out of the oil bath breather so it went through ok) and put the screw back in. Uh oh, the carb started leaking again. Not out of the body gasket but near the choke plate rod area - into the air breather assembly.
Pulled the carb back off. Checked the float level - set at 9/32" from body per spec for a M-S carb. Removed and inspected float, needle valve, and seat - all ok. Put it back togther and on tractor. Still leaks. Tractor runs much better at low rpm but is still too rich - no smoke but has the occaisional "stutter" or "miss" from being a little too rich. It runs better/worse/better/worse - when it runs slightly worse the governor opens slightly and it runs better. Air mixture screw makes little impact.
Any ideas? Should I set the float a little lower than spec? Would a gasket with a slight tear do this? I know an out of adjustment float will allow it to leak - and may allow it to run too rich - but this one is set per spec.
Any help appreciated - I'd like to get it back to no misses at 400 rpm idle ....!