Yamaha OX66 Alarm

We finally got the boat down to the coast and we did experience one problem with the motor.

I could run all day long under 4000rpm or so. Every time we kicked it up to over 45-4700, it would run for 3-7 minutes and then the alarm would sound. As the motor idled down (automatically), it would act like it was trying to throttle back up. I would pull the throttle back to idle, and the alarm would quit after about 15-30 seconds, and we would go again. The first time it did it, I stopped the motor and pulled the cowling. The motor did not feel hot, and the oil tank was at or above the top line. As I said above, it only did this above 4500 or so rpm. I played with the trim and up or down it still did it each time we opened her up.

I haven't yet changed the plugs or cleaned the O2 sensor, but I did change the small oil filter on the remote oil tank as well as the oil screen in the engine's main oil tank. By checking the remote oil tank, it was obvious that we burned oil on the trip. The engine always cranked right up and idled fine.

2003 OX66 200 Saltwater Series II
SX200TXRB

Any ideas???

Thanks.....Q

[jb123]

sounds like you need to change PRV

[boats.net]

It sounds like an overheat alarm which could be water pump, thermostats or pressure control valve.