View Full Version : Cooling question

05-12-2007, 08:09 PM
I installed a Mercruiser 140 degree stat this morning. The engine will run up to 165. I am running down the lake with the motor box off so I reach over and feel the manifold hoses and they are cool not even warm, the tops of the manifolds are mildy warm and the hose from water circulation pump to the T-sat housing is warm, but the top of the stat housing is cool, is this normal?

05-12-2007, 08:15 PM

A MARINE thermostat is 142 for your boat !!! Make sure it is marine
There are 3 very small holes in it that allow water to still flow through
it even it remains shut. Your temp should be about 160 while running.
Run it hard and shut it off it will go up.

Sounds like you are running OK. Keep a SPARE impeller aroung just incase

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05-12-2007, 08:21 PM
Thanks Jim, there are only a few marinas around me in central ontario and they are either OMC or Merc dealers, none of them carry PCM or Indmar parts. BTW the impeller is brand new.

Thanks again


05-12-2007, 08:25 PM
Always a good idea to have a spare impeller on hand so you dont get stranded