[ken privette]

1998 yam. 90, temp alarm going off @3100-3200 rpms. new impeller and pump, new thermostat, new sensor swtch. runs good around half throttle with no alarms. water not hot coming out of the discharge hole. touched the head when alarm was sounding, not hot to the touch. had the boat and motor for years, motor still in same position on boat. havent changed nothing. cant figure this one out, need help!!!

[sc_shane]

How much oil are you using? Does it seem less? Are you leaking any oil when it sits? What I'm getting at is you may not be using the right amount of oil and need a new oil pump or figure out why yours isn't working right...

[Silvertip]

Bypass valve should be opening about that point. If that valve is stuck shut the engine can't get enough cooling water through the thermostat alone.