OMC 4.3l temp issue???

[krustyCrab]

So ill make this post short and sweet... My engine temp sits at 140f while at idle on muffs, Goes up to 150 WOT on muffs... Same exact scenario on the water... I never get up to 160 which opens the thermostat and allows flow to the exhaust water jackets. Is this an issue? I figure it is, any advice would be appreciated. Something to note, I think this was an existing issue prior to me purchasing the boat, as there was no thermostat in it when i opened up the housing :-/

1986 OMC 4.3l v6

 

[Bondo]

Ayuh,..... My WAGuess is, Yer temp gauge is off 10°,.........

 

[Howard Sterndrive]

WOT on muffs? you can't really mean that.
1500 rpm max.

your pistons would be swapping holes at WOT no load

 

[800wildcat]

WOT on muffs? you can't really mean that.
1500 rpm max.

your pistons would be swapping holes at WOT no load

Actually, I think valve float will limit RPM's before the pistons decide to swap holes. Of course, valves floating and staying open while a piston is approaching can be a very nasty recipe depending on engine design (valve to piston clearence). As long as one stays below valve float RPM (or below redline), I can't think of another reason to limit the no load RPM to 1,500.

 

[800wildcat]

Someone else may want to verify this, but I think your raw water pump will pump cold water through the exhaust manifolds when the thermostat is closed. This is how most inboards are set up. The raw water feeds both the exhaust manifolds and the engine intake water hose. If your exhaust manifolds never get extremely hot, it's working as it should.