can't find pressure relief valve for 1989 90hp yamaha 2 stroke

[caddoman]

Does anyone know where the PRV (pressure relief valve) is on a 1989 90HP Yamaha 2 stroke? The alarm is going off at low speed and I would like to check the PRV. Have checked thermostat, thermoswitch, and water pump. All look good and water is pumping from the tell tale.

 

[robert graham]

Re: can't find pressure relief valve for 1989 90hp yamaha 2 stroke

Mine is a 1999 Yamaha 90C and the pressure control valve is under the same cover as the thermostat. It's an "X" shaped black plastic piece with a coil spring and a rubber grommet. Maybe they changed the design from yours? I had an alarm recently and I replaced the thermostat and that pressure control valve, both had a good bit of calcium/mineral deposits on them..... maybe sticking? Good Luck!

 

[caddoman]

Re: can't find pressure relief valve for 1989 90hp yamaha 2 stroke

Thanks Robert. Yeah, I realized it is under the thermostat after posting my question. I replaced the water pump and the thermostat yesterday and cranked it at home. Dealer didn't have the pressure relief valve, grommet, or spring in stock. I just cleaned the old parts up and put them back in because they looked fine. Water flow from tell tale is much stronger. No alarm at home. Gotta test her at the lake now. I believe the water pump was the problem. Thanks for the reply!