1966 Johnson 20 hp FD-20C

[pmp2220]

Does anyone know how the water cooling is suppose to work on this motor? the water is pumping in and comes out the water jacket on the motor and also threw the exhaust, is that normal ? sorry new the the boat world.

 

[RCO]

Totally normal. The water and exhaust both dump into the motor leg.

 

[oldboat1]

Water pump is in the lower unit, and should be replaced (impeller) if motor is new to you. Watch out for the flywheel, but touch the top of the head with the heel of your hand. If too hot to touch, the motor is running too hot (should be able to touch it for a few seconds or so). An infrared heat gun is a good investment -- should find 120-140F or so on the top of the head. 160 is too hot.

 

[F_R]

Does anyone know how the water cooling is suppose to work on this motor? the water is pumping in and comes out the water jacket on the motor and also threw the exhaust, is that normal ? sorry new the the boat world.

Don't know exactly what you are describing as "water jacket". But water should blow out the exhaust relief hole hole on the backside of the leg, and also out the exhaust outlet aft of the prop. However, I wonder how you can see that. That motor normally will not work on muffs. Even if you did somehow manage to get it to work on muffs, you cannot test a water pump by running on muffs. The hose supplies the water pressure, not the pump.

 

[pmp2220]

thank you for the reply, i believe i have it wrong... number #45 on the list is where the water is coming threw every so often. I will replace the gasket but is water even suppose to come out that?

 

[oldboat1]

Up at the top of the powerhead, you mean? The thermostat is up there under a triangular cover, and the seal can be a little dicey. It's a thick gasket under the cover, and probably better off getting a BRP one -- get a couple of them, while you're at it, just in case you mess one up.

Assuming that's it, you might first try to just tighten the cover down slightly -- do it evenly among the three bolts. It's the one at the narrow point of the triangle that tends to leak, in my experience.