External engine temperature

[vintagedave]

While tank testing my 1949 Champion, I would like to monitor engine temperature with a thermal gun. Any idea what would be a normal temperature on the head or body? At what temperature should I be concerned that it’s getting too hot?

[jw-in-dixie]

If it’s too hot to touch with your bare fingers it’s too hot. That applies to
old Mercs. Not OMC savvy.

JW in Dixie

[mr-asa]

I’ve been concerned with that as well, at meets I’ve asked a couple members if the powerhead was too hot. You couldn’t hold your hand on the powerhead for more than a ten or twenty seconds, but if you splashed water on it it wouldn’t boil off. Everyone I asked was ok with that, what that temp actually is….

Try finding an engine that runs well, with a known good cooling system, and measure that?

[brian]

If memory serves me correctly, that Champion could be the type with a metal water pump impeller with 2 water lines, one for intake and one for discharge in order to siphon water thru the engine. They work well on a moving boat but may not run cool in a tank. It’s been a number of years since I worked on one. Also, it is a closed system, there is no tell-tale to see if it’s pumping water and any attempt to add one will compromise the water flow.

[vintagedave]

Brian,
Yes, that’s the exact setup. I tank tested it earlier this summer and discovered I was missing an expansion plug. I replaced the plug and was hoping to test again before we try it on the boat this weekend.
Would it improve water flow in the tank if I removed the propelller to reduce turbulence?

[brian]

Dave,
I never tried it but It’s worth a try, just keep the rpm’s down. Then again, I wonder if there might be too little water circulation. Interesting, please let us know what your results are. The several I’ve run cooled well on the boat. It was nice knowing that the impeller wouldn’t disintegrate.

[Author]

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