overheating

[sunsetter99]

Hello I need some help here, I went to start up my 1999 sunsetter for the first time with the fake a lake attached. I never got any water out of the exhaust after 3 or 4 mins so I shut it down and checked the impeller, trans cooler screen all good free of any junk.  I then ordered a thermosatat and changed it then I started it back up and now very little water comes out mostly steam, engine temp never went above 170 but I shut it down after 7 or 8 mins. Normally water always comes out the exhaust and never leaks by the fake a lake because the impeller is sucking the water up, now the water sometimes gets sucked up but then sometimes just leaks. I pulled the water pump off and it looks ok   whats next??

[SayReponse]

I had a similar issue on my 2001 response this year.  Could never track down the precise problem, so I just changed all the cooling system components.  I made sure the trans cooler screen was clear, changed the thermostat, bought a new water circulation pump and a new impeller pump (with new impeller), and now everything is working just fine again.  Go figure.  I did buy the new high flow impeller pump.  All in it cost me around $300 to replace it all, and gave the peace of mind that i have new parts and shouldn't have the problem again.  At the end of the day, I think I was having an air leak on the impeller pump that was preventing good suction.

Edited June 17, 2019 by SayReponse

[solorex]

Sounds like you are not moving water through your engine (or at least not your exhaust).  So, either your impeller is not pumping, your water pump is seized or sheared off (not spinning) or your exhaust risers are rusted and blocked.

I'd buy a couple of riser gaskets (cheap) and check on the condition of your exhaust manifolds.  Has the boat ever been in salt?

[sunsetter99]

Never in salt ok I can check the manifolds thanks

[drh]

Rev the engine a few times to prime the raw water pump and see if that helps. Sometimes on the fake a lake it has a hard time priming.

[John I.]

Even brand new impellers have been known to be defective - i.e., brass insert spins without turning rubber impeller. 

[sunsetter99]

ok ill try a new impeller too