The first thing I would do is pull the valve cover and inspect the valve spring retainers for cracks and then I would check or have the valve lash checked. A service bulletin came out and said that this should be done between 10-12hrs and then again at 100hrs. I would check it every 25hrs. I only say this because I had a valve spring retainer break and the valve fell hit the piston and bent and stuck in the head. Polaris is paying for all new parts for my 150 and I am doing the labor myself since it happened two months after the warranty expired. I guess they are paying since the boat only has 53hrs on it, thank goodness. Other than that I have never had a problem. I really like the machine, I just had a mechanical failure. I have been in the aircraft industry for 22 years and I know that sh** happens.