Accepted Answer

Hi XXXX,
If I understand your question correctly, you do not have to add or maintain a water level in your ski for the purposes of cooling. It uses what is known as a raw water system, where it uses the water out of the lake or sea water and circulates that through the engine then out the exhaust. It does not use any kind of closed cooling system, like a radiator or heat exchanger. The water is pushed through the cooling system by tapping the high pressure side of the jet pump, the same pump that drives the ski, and diverting a small portion of that high pressure water into the engine cooling passages.
One thing you should also know is you want to make sure you evacuate that water from the engine when you are done riding for the day. You do that by starting the ski with the pump out of the water and revving the engine a half dozen times or so.
If you have any more questions, feel free to ask.
Thanks,
RSRBOB

Expert:	RSRBOB
Pos. Feedback:	100.0 %
Accepts:
Answered:	9/25/2009

Technician

Former Yamaha Factory Service Rep, Dlr Line Tech, Serv Mgr, G/M