How hot can my motor get?

Reg312

Petty Officer 2nd Class
Joined
Jul 12, 2009
Messages
139
As a new boater with an older boat, I'm getting to know the boats / motor quirks. Most of them operator error.

I have a mid 70's Merc 115. We were doing this weekend. Motor ran great but I did notice the cover was quite warm to hot but not sizzling hot. Temps outside were low 90's with a buttload of humidity. This is Missouri. I don't know if water temp maters, but I believe it was about 84.

So how hot should the cover get???? Like i said, motor ran great and looked like pump was operating normal.
 

Yepblaze

Lieutenant Commander
Joined
Jun 1, 2001
Messages
1,686
Re: How hot can my motor get?

How hot does your car get sitting in the sun?

Pretty hot.

As far as the motor goes, as long as the water is flowing out the squirt hole it's probably going to be fine.
 

Reg312

Petty Officer 2nd Class
Joined
Jul 12, 2009
Messages
139
Re: How hot can my motor get?

Thats what I kinda thought. But better safe than sorry.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,095
Re: How hot can my motor get?

Those inline motors do not have a thermostat. The cooling system is designed to keep them just cool enough, under normal use. If the impeller is damaged or the motor is overloaded, they will overheat and cause great damage to the pistons and cylinders.

They should run dead cold at idle and warmer at speed. You can tell how they are cooling, to a degree, by putting your hand on the port side exhaust cover. You must remove the wrap cowl to get to it.
 
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