Re: Why is my HD25 overheating?

[gjonz]

These motors run hotter than most. BUT…

The carb is cast into the exhaust housing. There was a bulletin that certain motors…probably early ones…get vapor lock because the fuel gets hot going into the carb due to an over-sized passage at the bottom of the carb. Instructions state to put a small wire pin inside that passage and it should clear the fuel issue.

BUT…

I would pull the exhaust housing and check for a plugged water passage. Is there charred paint on the motor?

There is a small grommet that the water tube seats into at the lower unit above the water pump. I have seen them close up and seriously restrict water flow. It should be open to a 1/4 inch or so. If it’s closed up even slightly it can cause issues.

And at the back of the powerhead there is a flush port that you may want to unscrew and blow air through. It looks like a drain plug for a lower unit.

Make sure the wobbler pump is tight on the eccentric on the prop shaft too.
Hope this helps!

Greg