What is the proper temp of head on a 3hp JW-10 ?

[Bryan/Aidan]

Hello, I am looking for some guidance on proper temp. for a 53 JW-10 runs fine just did a new impeller and cleaned all the water ports around the head. Ran for 5min came up to 150?

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[fleetwin]

These engines can be tough to gage engine temperature.  The exhaust manifold will normally get hot to the touch because it is not water cooled completely.   The cylinder head will get hot to the touch as well.

Engine temp is supposed to be checked on the right side of the engine near the ID core plug.

So, seeing temps of 150 on the cylinder head is not abnormal.

But, keep in mind there are many little water passages that get plugged fairly easily on these engines, especially in salt water.

[Bryan/Aidan]

Thank you for the reply, I will keep you posted, Ran air thru the side port I could fell it coming out at the lower end. I will test again later on. I do still work full time for myself. I did clean the head good with all the little holes.

one more question oil mix ? 16/to 1 or 24/to 1

Thank you Bryan.

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[bkrsdoz]

16:1 is the correct mix.

[outbdnut2]

The JWs don’t have a thermostat, so the temp it comes up to will change with the temp of the water it’s running in.  150 sounds OK.  If you are running in a small bucket, the water temp in the bucket can slowly increase too as the motor runs.   I flick water on the starboard side and/or top of the cylinders and if it doesn’t boil and spit, it’s not overheating.

Dave

[Author]

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