Reply To: 1975 Johnson 15R75C 15 hp

[Buccaneer]

Don wrote:

These things definitely have thermostats, and I would absolutely replace it if it is missing.  Won’t idle worth a darn without warming up and will foul plugs.

Be careful, there are two different styles of heads you might find on this thing, each has its own unique gasket.  Post a picture of the head and I will get you the gasket part number.   These thermostats are a pain to replace, but it can be done, am guessing this has not been used in salt water.

I watched the video, seemed to run OK, your mixture adjustment seems right.

Fleetwin, I guess I better look at the parts diagram, as I didn’t
see anything atop the head or block that looked to be hiding
a thermostat. Thanks!

P.S.- What do you know about those plastic gas tank cap’s
venting or pressure relief systems?

Prepare to be boarded!