Overheat alarm! ARRRRGH

[Follyboy]

After 2+ years for flawless operation, my '89 Johnson 60HP VRO heat alarm went off last time out. I had been running for 10-15 minute and alarm sounded when running @5K RPM. I immediatley shut down, allowed motor to cool down and idled back to the landing. I changed the impeller/housing just under 1 1/2 years ago and the thermostat earlier this year. The only change to the boat was a new gas cap, but it is vented and I do not believe this caused the problem. My game plan is to change impeller/housing/thermostat. Anyone other items/ideas to check? Motor is running pre-mix, hasn't set-up more than 3 weeks in last 2 years and ran great 2 weeks before.

 

[ob]

Re: Overheat alarm! ARRRRGH

I think you're on the right track.Post back with the results of your waterpump and T/Stat changeout.FYI ,I like to replace the inside exhaust housing rubber seal when I drop my lower unit for maintenance ,as they tend to get a little crusty and allow exhaust leakage .

 

[Follyboy]

Re: Overheat alarm! ARRRRGH

Thanks for the reply OB. Good call on the exhaust gasket too!

 

[Follyboy]

Re: Overheat alarm! ARRRRGH

Success! The new impeller/thermostat seems to have corrected the overheat problem. I ran the motor today for about 3 hours and no alarms. OB, I also changed the exhaust housing gasket as you recommended and the upper exhaust ports, just below the powerhead, seem to putting out more water and exhaust smoke than before. I'll bet there was some exhaust leakage before as you expected. Thanks again for the reply earlier. This site really has made owning a boat much easier and less costly.

 

[ob]

Re: Overheat alarm! ARRRRGH

Glad to hear you're up and running good Follyboy.Thanks for the update.