How hot should a HD25 run?

[burnt-clutch]

I was testing my HD 25 last night and ran it for 15 minutes. At the end of my run I noticed that the tiller handle was very warm ( at the base of the handle grip) and the carburetor was warm to the touch. Also, the motor was surging when running off of the high speed carb. I ran it in the test barrel for a minute before putting it on the boat and it was putting out the steam/fog from the exhaust hole at the top of the lower unit. Is it typical for these motors to run this hot?
-Karl

[frankr]

Because the carburetor and exhaust manifold are the same part, running too hot overheats the carburetor, making the fuel vaporize inside. This will show up as surging, among other things.

A common cause is the rubber seal mushing over the end of the water tube, at the water pump.

[gjonz]

There is a service bulletin showing some of those motors have too large of a passageway from the float chamber to the intake. They require a pin be cut and inseted in the passage toe reduce surface area which eliminates vaporization of the fuel by heat from the exhaust.

These motors have a flat head screw/clean oh at the front bottom of the float chamber.

Greg

[garry-in-michigan]

This from the Johnson service manual . . . 😀

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