My honda gx340 11hp was runnning fine one day then it just started sputering blowing black smoke but when you idle it down it purrs like a kitten I just put a brand new carb on it and didn't fix anything went through the whole motor only thing I found was the intake valve leaks a slight bit when performing solvent test... and now once all together motor won't start at all and it sputters like its trying but won't and there is gas in the air intake part?? I've been building bikes for about 3 years now and have never been so frustrated with a small engine I'm just wondering if my valve seat is ruined and what do I have to do to fix this? Thank you... charles...

Hi,
The machine is over-engineered from H... and you should first try unplgging all electrical connections and then plugging them back. Most problems such as this occur from this on Hondas.
Peace,
Clarke