I was running across the lake yesterday and my alarm started sounding off flashing the check engine light, oil can and horn. I had run out of oil in the remote tank. I shut her down limped her home filled up the tank and bled the air out of the engine mounted tank. Alarm still goes off. Beeps 4 times every 2 minutes. Engine runs good but it has gone into limp home mode now, will not put the Ranger 521 on plane. I pulled the sensor out of the engine mounted tank and it is dry. It seems that the sensor side of the tank does not have any oil n it. We started the motor numerous times and got a steady flow of oil out of the fill/bleed screw so I dont think there is still air in the system. Reading posts on the internet it also said that water in the fuel would cause the same issue. I took a fuel sample from the the egine mounted fuel seperator it looks good. Is the sensor in the onboard tank supposed to be sitting in oil? I unplugged the sensor while the engine was running and the alarm still sounds. Any ideas/help would be appreciated.

The motor mounted tank can have oil enough to supply to motor but not enough to shut off alarm. Check main tank caps for good seal, with soapy water. Check pickup screen in main tank. Check fitting where oil feeds the motor tank, make shure its clear. With motor running and oil cap loosened on motor tank oil should fill the motor tank and run over.

If it is completely full and running over, and the alarm is still sounding, most likely the sensor has gone bad. I had the exact same problem on a 2006 150 Optimax, except mine never went into limp mode. It would beep 4 times every 2 minutes though.

I replaced small engine mounted oil tank and it fixed the problem.

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