my guess is the carbs you have had are junk. unless the compression is crap, which you claim is good, the only two other things you need for the engine to run is spark and fuel. I assume that since you state the engine runs rich, then sputters, spark is ok, that leaves fuel being the issue.

Scott

The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me