cooling problem

[fliboi21]

hey guys have 1987 115 yamaha. right side therm. cover was hot to the touch, left side was cool. replaced therm. on right side and was still hot to the touch. water coming out of tell-tale is cool. any suggestions. thanks

[Hamfisted]

The water coming out of the tell-tale should be cool, it's your cooling water and hasn't been through the powerhead yet. I think maybe your left side thermostat is stuck closed? The thermostat covers should be hot once the thermostats open up. Are you having overheat problems?


Mike........ Miami, FL

[fliboi21]

the right side therm. is brand new, just replaced, i also thought that was the problem. but even with the new therm. the stb. side is still running hot. I don't know if the water jacket can be blocked on only one side. But im not getting overheating and i tested the termoswitch and the horn all work fine. just very hot to the touch on the stb. side compared to the port side. thx

[Ken]

fliboi21,
You may not be getting enough water pressure from your pump to flood the top of the starboard cylinder head. On my 2000 C115, the starboard cylinder bank is offset above the port. Yours is probably the same. If water pressure gets low, the starboard side will be the first to get hot.
If it has been at least three years since the last water pump redo, then I would consider it. You need to check for lower unit bolt thread corrosion anyway.
You may have some blockage in the starboard water jacket. Remove the bolt/plug that sits on top of each head and look down into the jacket. If you see a lot of sand/salt buildup, then I would flush with Salt-Away or Salt-Terminator.
Also, you might want to check the pressure relief valve to see if maybe it is stuck partially open and allowing the water from the pump to bypass going to the water jackets. I believe when this happens, you will see water coming out the two holes at the top of the upper case - even when the motor is cold and first started.
If you don't have one yet, get yourself a factory Yamaha manual. It will pay for itself.
Good luck,
Ken K

[fliboi21]

hey ken thanks for the advice ill check it out for a blockage. I have the seloc manual wich is great, but doesn't have much on trouble shooting this problem

[Fishman]

Cooling problem

I have the very same problem with a Yamaha 1997 P200 TLRV. The starboard side runs way hotter than the portside - stats are fine. Has anyone got to the bottom of this?

[boats.net]

I have the very same problem with a Yamaha 1997 P200 TLRV. The starboard side runs way hotter than the portside - stats are fine. Has anyone got to the bottom of this?

Start with a new water pump and inspect water pump closely to see if melted or distorted. Check pressure control valve. If that doesn't resolve it then remove cylinder heads and exhaust plates and clean water passages.