cooling/oil alarm

[stoney]

hey folks, i have a 1987 grady that i repowered with a 1994 yamaha 200 saltwater series. took the boat out today for some salmon *****ing, everything went fine , went about 45 total miles. while flushing the motor on the hose after about five minutes the alarm sounded so we shut the motor down and checked the oil. both oil levels were fine. we finsihed cleaning the boat, after about fif**** minutes went to start the motor and when we turned the ignition key alarm sill sounded. waited another 10 minutes and alram still sounded, then we started the motor for about 30 seconds , engine was peeing fine , after we shut her down she contiued to pee for a bit and i noticed the water was pretty warm. i have heard of some kind of popit valve that can get stuck. can someone tell me the location of this valve. i will look in my yamaha manual tomorrow. water pump was changed 2 months ago and i have gone out at least five times with no problems. any help where to look would be greatly appreciated.

thanks, stoney
1987 grady white w/1994 yamaha 200
san francisco

[boats.net]

Yamaha V6 engines will overheat when running on flush hose unless you have a double feed flush adapter and large diameter garden hose and good water pressure.

[Ken]

stoney,
Yeah, what boats.net said.
Also - the pressure relief valve (poppit) or regulator valve, I believe Yamaha calls it, is just a spring loaded water pressure valve that opens when the pressure in the cooling system gets above approx 20 pounds. On my V-4 block, it is located towards the bottom of the exhaust plate that is between the two cylinder banks. Yours should be about the same. The valve is under a dome-like piece of metal and has a rubber hose going to it.
The PRV can stick partially open when mineral deposits clog it, and thereby will allow cooling water to bypass the water jacket and dump out the bypass holes - the two holes at the top of the upper casing. If the PRV is stuck open, then you will see water dumping out these holes all the time. The PRV is fairly easy to remove and clean - you may have to move the CDI over a bit to get to it though.
If you are not having any alarms while on the water, then I believe your motor is cooling ok.
Good luck [img]smile.gif[/img] ,
Ken K