Overheating

[fireman4203]

I have a 1996 40 HP Mercury - 2 Stroke. Had a problem with it overheating. Replaced impeller, water is now peeing out but once we get going it is hot to the touch. It also seems as though it is not under enough pressure. Any suggestions? Tstat?

 

[Barnacle_Bill]

Re: Overheating

You should replace the tstat whenever you replace the impeller. It may be OK, but its cheap insurance. Also check the parts list for your motor for a poppet valve. They kick in somewhere around 2000RPM but I'm not sure if your motor has one or not.

 

[fireman4203]

Re: Overheating

Sounds good. Thanks for the reply. I have also read on this site that people will flush the cooling system. Is this done from bottom up or top down? Do I have to pull the lower 1/2 of the drive off?

 

[fireman4203]

Re: Overheating

An update on the saga.

I flushed it this morning and took it out for a lap. The water coming out of the pee hole after running is hot to the touch but the overheat alarm never went off. It seems like less water is coming out when at higher speeds. When we got back in, you could not hold your hand under the water because it was too hot, but you could put your hand on the engine block without burning yourself.

The other thing is that I could not find the tstat on the boat. The water discharge comes out of the top of the engine. Any clues? SN for the engine is 0G267379 - 1995 40 HP Merc with oil injection.