4 hp, Runs very erratic and excessively carbons up spark plug . I have cleaned about 6 times and have replace the diaphram & gaskets under the carboratore twice. The gas inlet screen is clear an seems to function properly. New: Air filter, Spark Plug and diaphram kit. When I clean the spark plug and restart it runs smooth for about 20 seconds then starts running erratically again. Any suggestions as to why it is running erratically, carbonning up and fowling the spark plug?

this is the swap and sell forum.....but to better answer this, how old is the engine, usage, etc. is it blowing black or bluish/white smoke.....?? if its white, make sure the oils not too thin, 30weight oil, and its not overfilled, and that the breather hose is not spitting oil into the carb...., if thats good, it may be time to either buy a new one, or rebuild it. and another thing, make sure the plug is gapped right ( .30 ) and its the right plug for it. right heat range plug for exact.