Do Mercury’s run Hot?

[david-bartlett]

General question of course. I recently got a 1979 Merc 7.5hp. I finally got around to starting it and noticed it did not send any water out of the pee hole, so I shut it down and pulled the lower unit.

Water pump impeller was shredded with pieces above and below the water pump housing. No thermostat either.

Replaced the impeller and thermostat. Took of exhaust cover and made sure no pieces were hiding in there.

It runs great, but the water coming out the indicator just "seems" to be hotter than it should. I have had a couple 9.8’s in the past and they seemed to put out some pretty warm water too.

Just wondering. Thanks.

[dave-bernard]

I would check the plastic washer under the power head they melt and restrict the flow. just remove it.

[david-bartlett]

I started it up with the exhaust cover off and ran it for about 5 seconds and it pumps like a fire truck so it is probably just me. Used to the old OMC stuff with no thermostat.

Thanks.

[billw]

You should be able to put your thumb on top of the block while it’s running and be able to hold it there, indefinitely. If it’s too hot to touch, it’s to hot to run.

Long live American manufacturing!

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