Hello folks, my yamaha 340 single mikuni carb have issues. I was thinking that the floats level in the carb was too high so the gaz continues to flow in after engine shut off(this sled always be flooded when hot : so hard to start-about 15 pulls with wide opên throttle).After lowering the gaz level on the carb ajusting the floats. No more problems the engine start in one pull. BUT at high rpm there not enough gaz in the carb so i can speed enough. Re-adjusting the carb a littl;e bit more fuel level in it. engine runs great, when i shut-off the engine, the fuel stop going in the carb(in one word: everyting seems to be OK). Compression is good, cold start always in one pull with the choke. any ideas of the problem ? tanks !!

I always shut the gas off if I stop for gas or get something to eat it works.

Try a new needle, seat and float set to the correct level. Make sure the vent on your gas tank isn't plugged causing pressure build-up.

Oh, and change the fuel filter.

Hello folks, my yamaha 340 single mikuni carb have issues. I was thinking that the floats level in the carb was too high so the gaz continues to flow in after engine shut off(this sled always be flooded when hot : so hard to start-about 15 pulls with wide opên throttle).After lowering the gaz level on the carb ajusting the floats. No more problems the engine start in one pull. BUT at high rpm there not enough gaz in the carb so i can speed enough. Re-adjusting the carb a littl;e bit more fuel level in it. engine runs great, when i shut-off the engine, the fuel stop going in the carb(in one word: everyting seems to be OK). Compression is good, cold start always in one pull with the choke. any ideas of the problem ? tanks !![/b]
Probably a pain but what about installing a fuel shut-off petcock and turn the fuel off when you stop. This way you can achieve the best of both worlds.
Richard