Hello im new to the pwc world and im looking at getting a 1989 kawasaki stand up jet ski with a 550 engine. The thing is im told its been rebuilt twice due to water getting into the engine through the cylinder head. I'm not sure if this is the real cause of it breaking down but basically im asking whats the cheapest fix to this problem. do i need to buy another cylinder case? new cylinder head? help please any information would help thanks