Water pump?

[Blackntan90]

How do you tell if the recirculating pump is bad - it seems to me that my pump may be on it's last leg. I ran her on the hose yesterday, and tried the old bucket trick with the hose dumping into the bucket and the 'plunger' sucking from the bucket. Well it did pull water into the strainer, so I know my impeller is working- just replaced it so that is good! But it seems that if I run at or near WOT, if I come to idle no wake speed she gets rather warm(200)- if I slowly ease back gradually she stays around 160. I replace my impeller every year, but always wondered how long the main recirculating pumps last? I f anybody has some insight on this I would like to hear as we have a trip coming up in a couple of weeks and do not want to be at the lake with no boat! -Rich

[docdrs]

You may want to check,replace your thermostat. A 160 tstat starts to open at 160. At high rpms the tstat may be open a little as the pressure from the impeller is pushing cool water into the engine and allowed to flow out thru the tstat. When you shut down a hot engine to idle the block is a heat sink and not a lot of water is flowing thru from the impeller due to low rpms. As the tstat opens up more water is allowed to flow thru the engine but at a slow rate. The engine temp sensor located at the top of the engine may be reading a pooled hot water spot giving you high readings. Next time you bring it back to idle quickly ,engage neutral and rev the engine and watch the temp gauge. It should quickly drop back to 160 with slight revving of the engine.

[Blackntan90]

Thank you, Doug. I did replace the thermostat, but I will try revving in neutral and see what that does.