Running Temp

[NeptuneMadness]

What is the average/ Ideal running temp for a 66″ 6hp Evinrude? Thank you

[Mumbles]

The stat is rated at 143° F so anything much above this would be concerning. Mind you, some motors do have hot spots on them which can be well above 143 but are nothing to worry about. If the motor runs hotter than 160° F, minerals can leach out of the water causing buildup in the water jackets and that’s why outboards run at lower temperatures than vehicles do. A hand held infrared thermometer works best for checking temperatures.

[NeptuneMadness]

Ok, I keep hearing about running temp. but haven’t seen WHAT the average temp should be. I need to get the infrared thermometer so. Thank you! Besides, a rough idle and more fuel consumption, what are really the bad effects of running without a Thermostat?

Thank you for your time!

[frankr]

You will hear all kinds of opinions. But when it comes down to it, the benefits of the ‘stat is why they put it in there. Benefits such as better, cleaner running in cold weather or cold water. Do you know that OMC sold that same motor (powerhead) on a cheapy lower unit and strangled down to 5hp to compete with Sears, etc? The resulting 5hp did not have a thermostat—then they sold a thermostat kit as an accessory.

EDIT: One service manual says it should run 1500-3000 RPM on a boat @ 125 degree minimum, and less than 163 degrees.

• This reply was modified 4 years, 5 months ago by frankr.

[NeptuneMadness]

Besides not running at peak, or full power, no stat won’t really HURT it though? I still need to figure out why the issue when I had it in, but I’m ready to hit the water! Nope, I did not know OMC did that.

Thank you for the information and your time!

[frankr]

Like I said, you will hear all kinds of opinions. Some may even be valid. Like carbon buildup, or failure to burn off moisture. Open to debate, I suppose. I do know that too-cool running in a 4-stroke will build up sludge in the crankcase. But a two-stroke crankcase is self cleaning. Hey, lots of outboards never did have a thermostat. Let the debate go on.

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NeptuneMadness

[JOHN HOLBIK]

We ran a fishing resort from 1949 to 1995 so I have ran the same series motors with thermostats and with out,I have saw no difference in carbon build up or plug fouling.
I have a Evinrude Angler 5hp a 1965 model it uses the same style lower unit as the 4hp Yacht twin props are scarce as hens teeth.The 5hp is a very nice running good trolling outboard.I run a lot of weedy rivers and lakes on my trapline and use OMC 3 and 4hp weedless lower unit motors.I have tried for years to figure out a way to use the weedless lower unit on the 5hp Angler but the prop size is too big for the weedless lower unit.It would be great to have the speed of the 5hp with a heavy load.
The invention of the weedless lower unit by Finn T Irgen was one of the high points of better boating you run right threw weeds no stopping to clean off weeds.

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NeptuneMadness

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