Testing the water flow on 1981 9.9 HP Evinrude

[PickyBiker]

I just got a 1981 9.9 HP Evinrude running after being stored 6 years. I am concerned about the cooling. There is a water hose running to the rubber cups over the intake area. The water is on fairly high but when the motor is started, there doesn't seem to be a stream of water coming out anywhere. I don't see a thermostat anywhere and I removed the lower unit to inspect the pump and it all seems fine. Where does the water come out on these engines and how can I be sure it is cooling?

 

[flyingscott]

The water should come out the pee-hole on the back of the motor also out the exhaust relief and the holes above the cavitation plate. The thermostat is down by the hood release on the head. First thing I would do is replace the water pump assembly after 6 yrs could have a spun hub

 

[oldboat1]

should get a spray of water out of the ports on the back of the leg, even if the tell tale is plugged up. If spray coming out, test surface temp on the top of the head (shouldn't be too hot to touch).

 

[PickyBiker]

Removed the lower unit and found the water pump to be just fine. The impeller is very flexible and resilient. Applied water pressure to the water pipe and nothing would flow. Pulled the thermostat and it was completely gunked up. With the thermostat removed, there is a free flow of water. There is now a thermostat, seat, and Water Cover gasket on order.

I noticed the thermostat does not have a bypass hole in it which tells me there can be no water flow at all until the engine warms up. In cars, the bypass hole allows a minimum of water to flow to allow the car's heater to produce a little heat while the engine is warming up. Guess that's not needed in outboards.

It still seems strange to me that you wouldn't see water circulating while it is warming up.

Thoughts?

 

[scout-j-m]

I was actually reading through my 1982 9.9/15 hp factory service manual last night and specifically remember it stating that this engine's t-stat does have a bypass hole. Maybe it was juts too gunked up to notice?

 

[PickyBiker]

Bingo. There is no hole, but where the movable part seats against the top, there is an indent in one of the arms that forms the pointy tip. I had to cut it open to see it. That's where the water seeps by to initially fill the water cavity. It forms a very small opening and it was completely blocked with green copper oxide and other crud.

That's what I call hitting the nail on the head scout-j-m !