# Yamaha 60 hp four stroke cooling issues



## buddy48 (May 10, 2014)

I was hoping someone could offer me some help in trying to figure out my cooling issue. I have 2007 60 hp yamaha four stroke. I replaced the water pump impeller, and all associated parts/gaskets today. Old impeller wasn't in terrible shape. Took it to the lake for a run. When backing it off the trailer I noticed that the stream was stronger than it has been since I bought the boat. So I thought everything was going great. Let the boat idle while at the boat dock while I was parking the truck. Here's where it gets strange..

While idling the temp alarm/buzzer went off. I noticed that the stream was not as strong as before. Cut the engine off. Started it right back up and no issues. Run down the lake and it beeped for a second after I had run it for 2-3 minutes. Nothing else for 5-6 minutes. Cranked it up and let it idle while I was fishing and the buzzer went off again. Felt the water and it was luke warm.

While I was at home I did clean out the pee hole and it felt like when I put the piece of wire in there it was slightly restricted. 

So, I was wondering if the the issue may be the thermostat. My theory is that the slightly blocked pee hole may have kept the water in the engine long enough to cool it off and now that it is clear that it may not since possibly the thermostat may be bad? I know that sounds crazy, but I don't know what else it could be.


What do you all recommend for me to do/look at?


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## buddy48 (May 11, 2014)

Come on boat mechanics! I need some help!!


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## 1gr8bldr (May 11, 2014)

The rubber star looking paddle that pumps the water, the leaves or paddles can go foward or backward when installed. I once had to reverse mine after having changed mine. Same issue as your having. It will work backward, just not as it should


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## 1gr8bldr (May 11, 2014)

After rereading your post, I now see where you cleaned out your pee hole at home rather than at the lake. This is likely your problem.


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## buddy48 (May 11, 2014)

Did some more troubleshooting today. Hooked it up to the muffs, cranked it up and nothing came out of the pee hole. Not sure if this is typical, but it may not have ever come out of the pee hole when idling in the yard. I felt the block up near the top and it was getting hot so I shut her down. Took the thermostat out and the water jacket behind it was bone dry. While I had it out I put it in some water on the stove and the t-stat opened up like it is supposed to. Not a very technical test, but maybe it indicates that the t-stat is working.

Then I hooked up the hose to the flush connection. Turned on the water and got good flow of course out of the lower unit and the pee hole. I did this while the thermostat was out. Nothing was coming out of the engine at that location. Put my finger over the pee hole and there comes the water out of the thermostat location. Took my finger off of the pee hole and water continued to flow out of the thermostat opening. Replaced the thermostat and moved to the next step.

I removed the foot again to check the water pump and everything was installed correctly including the impeller turned the correct way.

I'll see if this has it corrected the next trip to the lake. Hopefully it was just a blockage that restricted water flow at low rpm's since it would over heat at idle but not when wide open.


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## Lukikus2 (May 13, 2014)

Sounds like an obstruction in your pee hose. Even though you cleaned it out, take it off the thermostat and see if you can blow thru it easily. Bugs will stop them up when sitting for prolonged periods of time. I always use to put a piece of masking tape over mine when not in use. If you forget to take it off the water will blow the masking tape right off. Good luck.


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## Wild Turkey (May 13, 2014)

Was the impeller in tact when removed. Ive seen pieces go down into the block via cooling jackets. More than pee hole may be blocked.


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## buddy48 (May 13, 2014)

The impeller was intact. However, there was a small piece of rubber about half the size of a bb that was on the outside of the stainless steel cup that the water pump sits in. I inspected the impeller and it didnt appear to be damaged so I assumed that I slightly pinched the edge of one of the vanes. A small piece of this may have gotten in a jacket somewhere, but I figured it was so small that it wouldn't block anything.


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## Bilge Rat LT 20 (May 25, 2014)

The pee hole is piped in before the water goes into the powerhead. it just shows that the waterpump is pumping NOT that any water is flowing thru the motor.

Check the pressure regulating valve, poppet valve.
This is usually the cause of your issue.

It dumps excess water pressure out of motor.  If it is stuck open the water pump may not create enough flow at idle to fill the motor with the poppet dumping.
It is a spring and plastic plug. Remove clean or replace, it is cheap.

When at home your waterhose/muffs may not have enough flow to properly fill motor and come out of pee hole too. This is common.
Get a plastic 55 gall drum to run the motor in at home.

The T-stat is working? opening and closing?
Is the water pump housing good? not warped or melted due to exhaust overheating it?

The poppet valve is what your issue is usually caused from, check there first.


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