Constant alarm beeping on Mercury Classic 40

The other day, the alarm started beeping (beep, beep, beep,......) and won't stop. The cooling water stream is fine, and the oil level in the oil injection tank is fine. I have done some research on the Internet and have come to the following conclusion so far: (1) a continuous beep would indicate overheating, which is definitely not the problem, (2) an intermittent beep that continues is an indication of low oil level, which is also not the problem. An old post said that most likely the magnetic washer on the float of the oil level sensor has dropped off. The post said there was NO FIX for this problem because the float was placed inside the tank during manufacturing (by blow-molding of the tank) and therefore the float is not replaceable. That is a bummer. Of course, if that is the only problem, then just disconnecting the oil level sensor and keeping a close eye on the oil level is a possible solution. My two questions are: (1) Is low oil level the only reason the alarm will go into a beeping mode? (2) Is it true that the oil level sensor is not serviceable?