To keep the motor cool while testing it, there is a plug at the bottom of the cylinders which can be removed and replaced with a fitting so you can hook it up to a garden hose. They will over heat trying to run it in a barrel as they need the motion of the boat and the thrust of the prop turning at full RPM for a few seconds to prime the motors pressure/vacumm cooling system. Once it’s primed, speed can be reduced.
With no conventional water pump or impeller, water is forced into the motors intake at the rear of the prop by the prop and exits in front of the prop being pulled out of the motor by the low pressure area in front of the prop. Simple design but it works.
KA models are notorious for having the exhaust pipe coming from the cylinders plugging up with carbon from years of using 30W motor oil at the 8:1 ratio. This might be why the cutout was removed, so the motor could breath. With the tank off for repairs, it’s easy to remove the exhaust cover and clean it out.
First photo shows the motor with exhaust cover removed and a 90° pipe fitting installed below the cylinders for a garden hose.
Some Bondo work and paint for the tank.
