Mercury 150 2-stroke problem

[SFLbass]

I have just recently bought a boat with a 1996 150 2-stroke on it and i bought it from a older man who had cancer so it hadn't been run in awhile.

The oil alarm will not turn off even when the oil tanks are full. its done it once before and I took the float out of the oil resevoir on the motor and moved it up and down and put it back, then I made sure the caps were tight and not leaking on the oil tank that is on the boat, started it up and the low oil alarm turned off, so the next day im driving the boat stop to fish and begin heading for the trailer when the alarm goes off so I shut the motor off and repaet the process I did the time before, start it up and the alarm is still on. I troll back to the trailer and take the boat out of the water, start it up and the alarm is still on, so I figured the problem was with the float on the outboards oil resivor, so I disconnected it but the alarm still stays on, so that tells me its not the float, so I read the manual and it says the oil alarm and water in the fuel filter alarm are the same but when its water in the feul filter a red light on the front of the outboard will be on, but its not. so I disconnected the fuel filters water sensor but the alarm stays on, so thats not the problem either.

It has me baffled. I am familiar with 2-stroke dirtbikes and I know older bikes had oil injection and the pumps would go bad all the time and you would have to premix your fuel

oh and when I turn the ignition on the oil injection pump makes a buzzing noise.

I've also heard that the pickup tube for the oil could have sludge in it.

I dont want to run the boat unless I know its getting oil cause i dont want it to seize up on me.

I also heard this problem is pretty common. If its the oil injection pump, any idea on what a new one would cost, cause if it expensive im gonna start premixing.

If anyone is familiar with this engine any advice would be greatly appreciated.

Thank You