Merc 500 water flow

[NormT]

When I noticed no water flow from the pee hole of my friends 1968 50hp Merc 4cyl., I assumed it was the water pump. But, the pump is fine. The pee hole is not clogged. I tried water pressure and then compressed air back through the hole and its tube, but nothing flows. There's no other water flow when I hooked the cups and hose to the lower unit.<br />I can't find anything that looks remotely like a thermostat housing either on the engine or in the Selock manual. The manual shows a thermostat being replaced into a baffle, with no hints of where that really is. So I don't know if the engine has a stuck thermostat.<br /><br />Any suggestions about where I should start to solve this problem?

 

[Nandy]

Re: Merc 500 water flow

Norm, I had that problem with mine also. There is not a thermostat on that motor. The Seloc book covers multiple powerheads. Anyway, mine had the grooves on the outer exaust plate clogged. Also the inner exaust plate was badly corroded so I had to replace it. <br /><br />Inner Exaust Plate $66.05 904211<br />Outer Exaust Plate Gasket $5.30 27 854913<br />Inner Exaust Plate Gasket $5.90 27 854924<br />Cylinder Block Gasket $4.40 27 85487<br /><br />That was about it for me. Make sure you label the wires and take photos to make it easire to put back.<br />Good luck...

 

[Bowjamer]

Re: Merc 500 water flow

Norm, I had that problem with mine also. There is not a thermostat on that motor. The Seloc book covers multiple powerheads. Anyway, mine had the grooves on the outer exaust plate clogged. Also the inner exaust plate was badly corroded so I had to replace it. <br /><br />Inner Exaust Plate $66.05 904211<br />Outer Exaust Plate Gasket $5.30 27 854913<br />Inner Exaust Plate Gasket $5.90 27 854924<br />Cylinder Block Gasket $4.40 27 85487<br /><br />That was about it for me. Make sure you label the wires and take photos to make it easire to put back.<br />Good luck...

can I run it with clogged tell tale channel before the pipe to the pee hole . if I attach a temp gauge to motor that has new impeller

 

[Bowjamer]

can I run it with clogged tell tale channel before the pipe to the pee hole . if I attach a temp gauge to motor that has new impeller

and its nice to be here among boaters

 

[Bowjamer]

When I noticed no water flow from the pee hole of my friends 1968 50hp Merc 4cyl., I assumed it was the water pump. But, the pump is fine. The pee hole is not clogged. I tried water pressure and then compressed air back through the hole and its tube, but nothing flows. There's no other water flow when I hooked the cups and hose to the lower unit.<br />I can't find anything that looks remotely like a thermostat housing either on the engine or in the Selock manual. The manual shows a thermostat being replaced into a baffle, with no hints of where that really is. So I don't know if the engine has a stuck thermostat.<br /><br />Any suggestions about where I should start to solve this problem?

I did the same with my 1966 500 Merc that has a new impeller and was wondering if I install temp gauge can I run it hoping engine is getting enough cooling water to rest of motor by monitoring temp