I had a new Kaw. FH541V installed less than a year ago. Now when i start the motor it struggles to reach its normal 3500-3600 RPMs. I smell strong fuel fumes and some times it backfires. These symtoms started about 6-8 weeks ago and have progressively gotten worse. Now i can't even engage my blades without the engine stalling. I have tried different positions on the choke and also running the engine with out the air filter. The engine will start but it spits and sputters really bad and idles about 3100 RPM. The engine jumps to full RPMs and then immediately goes back down. Any advice?