How hot is overheating? Small outboards 6-8HP

merc20076

Petty Officer 2nd Class
Joined
Sep 9, 2009
Messages
156
I just picked up this weekend another 7.5 HP Evinrdude ( E8RCIC ) that had a busted lower unit, probably ran out of oil, the gears were all scrap. Anyways, having a spare lower unit from my first Evinrude 4.5HP I was in business if the motor was ok. And yes it's ready to use, just need a new cover gasket for the tstat before the real test.

And yes, my cheap compression tester reads 95-100 PSI on both cylinders, motor runs really good and it does have a tstat but the head gets hot after 3-4 seconds touching it. Is this ok or it overheats? I'm planning to get a laser tstat to check motor temp.

My '83 7.5HP Johnson for my SIB doesn't run good with a tstat but very good without. What can cause that? The tstat was installed the same way and it did opened. I think it will be harder on gas if I don't run it with it...
 

AlTn

Commander
Joined
Mar 9, 2010
Messages
2,813
Re: How hot is overheating? Small outboards 6-8HP

from a factory manual for a 1978 9.9...using thermomelt sticks...a 125 deg. should melt...163 deg. should not..so..seems somewhere in that range is ok...145 deg.is a figure I've read here often
 
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