Oil Pump problem

[Via]

Hi,

Wondering if you can help, i am having a problem with the oil control unit on a yamaha 140hp 89 motor, the problem is that my pump will not turn on when the sensor indicates low oil in main tank. I have tested the pump to see if it working with a battery and it works fine. When you push the emergency manual overide switch on the oil control box the pump will fill the main tank from the reserve tank. Have also tested the float switches in both tanks with an ohm meter and they seem to be working fine. Would anyone have any suggestions on what would be causing this problem, i think it is the oil control module but not sure?

btw, the indicator lights always indicate low oil but when flipping the sensor upside down it would show a red no oil sign.

Thanks
Via

[boats.net]

If the oil tank in boat is low on oil or if sensor is bad and showing low oil( yellow light on tach) when tank is full of oil then the oil pump will not transfer oil to engine tank.

[stpabr]

I had a similar issue, where sometime the remote would refill the engine tank, and sometime it would not.

I found a bad ground wire on the remote harness.
I'm looking for a new harnes to replace it, but it is about $78.00 for a 20 ft harness.
I'm thinking I can resplice the ground wire in the harness.

[Via]

The reserve oil tank is full, and when i simulate a low oil in engine oil tank (main tank), it will not pump anymore oil from the reserve to the main tank with the low oil (yellow light) indicator on, and i have changed the sensors with a spare with still same problem, i dont think it is a grounding problem as i have checked all wiring. and other suggestions?