hey i have a 94 650 waverunner, and after about 10 minutes or so it starts stalling. it stills idles and seems to run fine just won't rev. sometimes if you turn it off and start it again it is fine for a while and then it starts playin up again. when it is running well it revs hard and seems fine. it has had new plugs, leads, fuel, filters and has recently been tuned at the shop and had a new carb kit through it. it has just had a new battery as well. any ideas would be great.