warning alarm sounds constantly

[Lee tomandl]

My 40 horse, 4 cylinder Merc has an alarm that sound all the time. I disconnected the temp sensor wire, and the float switch wires on the oils resevoir, it still sounds.

What else is there to look at???
Lee

[boats.net]

Could be oil pump sensor, if has sensor on oil pump remove pump and make sure oil pump drive shaft turns when engine crankshaft is turning or warning module bad.