Hello,
I have a 17 hp Kawasaki single cylinder engine on my J.D. commercial mower.
At the end of last season, it would backfire at start-up. The engine had to e choked for it to start unless it was hot. Other wise it ran great.
When I pulled it out this year, it would not start. I took the carb off and throughly cleaned it out. I took the over head valve cover off and checked the valves( they did not appear to be stuck and had a little play at the right rotation). I bought a new plug.
Now for the problem.
While it was cranking, it would sputter and backfire gas and/or flames out of the carb. If i put fuel in the carb or plug, it would start eventually and run fine.
But the minute i shut it down, it would not restart again! I did have to move the choke back and forth to get it to start however. Eventually, even after running for a few minutes, it would slowly stall out.
I have not checked the flywheel key yet

Any suggestions would be greatly appreciated.