I own a 99' MXZ 600 with 5800 miles on it. In the fall I pulled it out of storage, and started it and found it to run great. I put it in my yard for about a months time in the Fall where it sat out in the elements. When I got it in the garage to work on it I found water in the motor as I pulled my pipe off. I got the water out and got the motor to run. The problem I am having is that of a knock in the motor. I have good presure and the snowmobile starts on the first pull, but still there is a knock. When spinning the clutch and holding steady pressure on the tops of the pistons there is no play. Looking for ideas before I rip it apart to take a look inside, because I want to run it but don't want to break anything.