4.3 mercruiser running hot at high rpm's

[fishaholic130]

I have a 280 larson cabrio with twin 4.3 mercruisers with alpha one drives they are saltwater cooled the port engine is giving me trouble when I go over 3800 rpms the tempature will rise a little past 175 and the alarm goes offif I back down a couple rpm's the temp. goes back down also both engines are running at 175 is that the right temp. for these engines

 

[Chris1956]

Re: 4.3 mercruiser running hot at high rpm's

Mike, First check to see if the water intakes on the outdrives are clogged. The barnacles get into my Alpha. If that's not it, check the thermostat for proper operation, or just replace it. If that's not it, you need a new impeller.

 

[fishaholic130]

Re: 4.3 mercruiser running hot at high rpm's

Thanks for the quick response I cleaned the outdrive intakes and the impeller and thermostats were changed at the end of last season also has new rises put on at the end of last season