my sled runs fine until you give it some and then it starts to sound like its hitting a rev limiter. It doesnt bog, but it just stops accelerating and starts sounding all choppy. I was looking at the power valves, and im thinking that the motor that operates them might be toast. i can pull on the cables and hear the valves open and close, but if i rev it up and watch where the cables hook in, it never moves, not even a little. anyone got any ideas? its got good lower end power, and i can drive around up to 6000 and have the skis lift up with ease. is there a way to test the motor?