we have a little jet boat, and it overheated on me twice, once pulling some guy, and the other was just cruising around the lake. Not sure if this will help or not, but it felt like someone was picking the back end out of the water. In any case, I took it for service,and they took off the impeller case, and there was a lot of weeds, and even treeback in there. That's what the prob was. It's run fine ever since. And we were lucky cause that stuff could wreck the impeller. Also the guy told us that a jet intake could suck up most things at full throttle from 2 feet below the hull. That's quite a bit.