15454S 15 HP Evinrude water issues

[Bullie]

I have been working on a 1974 15 hp Evinrude for quite awhile. The latest issue is no water flow. It has been one of "those" 74s in that the ignition system has been a major pain. I finally got it started and no water flow out of the motor at all that I could detect. I monitored temps with an infrared thermometer and shut it down when the temp went over 150 and I still didn't see any water. The impeller was in decent shape and the pump looked good so I decided to check water flow before reinstalling the LU after putting in the new impeller. I connected a hose to the copper pipe and using low pressure tried to push water through the motor. No water flowed up the clear hose at all. I tried to blow air up the hose. Same thing. I am reasonably sure I know what is wrong but I wanted to describe the issue to you guys before undertaking a big job (for me at least).

Upper water tube grommet?

 

[flyingscott]

Sounds like it and change the thermostat while the powerhead is off.

 

[Bullie]

flyingscott, I finally got around to removing the powerhead this morning. I was surprised to find the water tube grommet in decent shape. I was fairly certain that would be the issue. When I removed the cylinder head water cover the thermostat was definitely non-operative. The little spring and plunger at the top of it fell out as I opened it up. I have ordered a new thermostat for it and I have a new gasket. What else should I check? I don't see any corrosion or salt in this motor. All the bolts have come out easily enough. I don't want to button this thing back up without making as certain as possible that it was the thermostat stuck closed that is causing the problem.

If the thermostat stopped working in the closed position could no water get around it at all? I guess I assumed that water should flow to some degree whether the thermostat was open or closed.

 

[flyingscott]

Take the hose and run water through the block and down through the lower unit make sure the intake isn't plugged and inside the block. When you check the block put the waterjacket back on make sure the block is free. Water should always flow may take a couple seconds but it comes out the exhaust relief holes pretty strongly.

 

[Bullie]

Ok. Will do. I found a couple of blockages that looked like dirt dauber mud. Maybe I got it.

 

[flyingscott]

Those will do it