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Wondering if someone could shine some light on my problem. I have a 87 115 that is running hot on just the stbd. side. replaced the thermostat...with no change. ran some salt-away through the motor thinking i might have a partial block....no change, ran the motor very briefly with the termostat out just to see if water was actually getting to the head.. plenty of water. any ideas???? thanks
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Do you have a Water Pressure Gauge? Is it getting hot at Idle or Full Throttle? How old is the impeller? -
fliboi,
How do you know it is the starboard side that is overheating? Do you have a temp gauge on that side? Are you getting an overheat alarm and the motor is going into rpm reduction mode? Have you removed the starboard thermo switch and tested it?
I know this is a lot of questions, but it helps to troubleshoot. I have seen thermo switches go bad and close as soon as 130 degrees, giving a false overheat alarm - they are designed to close at around 185.
Your water pump could be weak if it has not been replaced in the last three years. There could be mineral/salt buildup in the heads - I have found that Salt-Away and Salt-Terminator don't do much to remove heavy deposit buildup.
If you do not want to do a water pump repair right now, try leaving the thermostats out and see if the extra water flow will keep the heads a little cooler - do a water pump repair in the off season.
Also, check the PRV (pressure relief valve) to make sure it is not stuck partially open and dumping cooling water pre-maturely.
Good luck,
Ken KComment
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thanks for the replies. the water pump is about 4 years old. so that is due. I guess im worried because the water pressure guage is reading pretty close to what it has been for the past couple of seasons. The motor itself is not overheating persay( i am not getting the horn or reduction in rpms... and the circiut has been tested and works)...Ken the only reason i say its the strb. side is that when you put your hand on the thermostat housing it is very hot to the touch(with brand new thermastat).I have twins, and the temperature to the touch is much hotter then the feel of the other motor and the port side of this motor. thanksComment
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sounds to me like youre due for your 4 yr service soon !Comment
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fliboi,
Really starting to sound like you have a restriction in that starboard head - or maybe a bad head gasket (hopefully, not). I would first leave out the thermostat on the starboard side only, and run the outboard and do your "feel" test to see what difference, if any, that makes.
Also, considering the age of your outboards, I would do a compression test - you could have a blown head gasket and you need to find out now.
Removing heads and replacing head gaskets is not real complicated, and there are sacrificial anodes in the cylider assy under the heads that need to be replaced every 400-600 hours anyway. Also, while the heads are off, the water jackets can be cleaned out.
Bottom line - if the compression in all four cylinders is ok, do a water pump repair even though the pressure gauge is still showing same as it has last couple of years. Check that PRV and try with/without thermostat on that starboard side. If none of this works, pull the heads anyway and have the water jackets cleaned out and new head gaskets.
I know this sounds overwhelming all the possibilities - I am fighting an overheat condition now on my C115 - also on the starboard side. I have pretty well determined that it is a weak water pump, but I don't want to take the time from fishing to do a repair, so I just removed the thermostats as a temporary fix until the off season this winter (if my pump will make it that long).
Good luck,
Ken KComment
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