Hello all! I have a Yamaha Grizzly 600cc 4 wheeler that we use to do leaf cleanups. The machine runs and works great for pulling a tarp full of leaves...however there is a problem w/ the engine... The problem is, at random times when you open up the throttle all the way (not pulling a tarp when doing this!) The machine will sputter and loose ALL power. If you gas it, the machine will sound like it will stall and backfire, however if you wait about 10 seconds without opening the throttle, the machine will run perfectly again for a few more minutes then the problem will repeat. Any ideas?