How hot is too hot.

No not me, the boat. I am fighting an overheat problem. Running about 180 degrees at 2500 rpm. Ran around 160 last year. Has been hot since un-winterising. I have been running without a strainer in the basket for years, but the gasket is present and the basket is tight. I back flushed the tranny cooler and then from the tranny cooler to the lake pick up. I put in a new impeller but the old one looked great. I have inspected the hoses and tightened all the clamps with no improvement. I will inspect the thermostat next, and I bought a new in line strainer with the wire screen to install(Grainger, I love that place!). I want to check the engine temp with the thermoscanner, what part(s) should I target? How hot can I run the boat without doing damage? Will 180 do any harm or can I have a little fun if I put it in the water and still have the problem? Will dirty electrical contacts raise or lower the reading? What else have I missed?

Dave,
Resistance from bad connections will lower the reading on the gauge. Who's brand of impeller did you use? The OEM is best as there are reported problems with the Sierra.

Pete, It is a sierra purchased locally through a fairly reputable inboard sales and service dealer. The fact that it runs the exact same temp with either the old or new impeller installed makes me think that it is not the likely problem. Andy good to know about the 200 degree max. The thermostat is rated around 140 and it always ran 155 to 160 under load. I am also thinking air. I can focus on the suction side of the pump correct? And if I see no air going through the strainer than I should focus between the strainer and the raw water pump?

double check you don't have pieces of the old impeller lodged in the T-stat housing. Mine was running hot with a new impeller and no air leaks. After pulling the T-stat housing I found about 15 pieces of old impellers lodged in there. When the pieces break off they have to go somewhere and could be restricting waterflow.

Tim, it runs hotter with higher rpms. Specifically over 2500.

Ahhhhh!

81nautique wrote: OverMyHead wrote: PETE, I saw in the thermostat thread you asked about a flush kit. What was that about? Pete's going to install a flush kit so he can wax his toilet bowl!! Inside joke

Alan,
I used a new toilet bowl cleaner. It has teflon in it so it coats the bowl so nothing sticks!! Maybe I should try it on the Tique hull??

Dave,
I mentioned the flush kit since they can be a source of sucking air on the suction side of the RWP.