Boat Motor Help

I have a mercury 150 xr6 on my boat, it is a 99 or 2000. The buzzers started sounding on it this spring. We just bought the boat off a friend and he has never had any trouble out of it. We had the water pump replaced, and the oil resevoir on the motor is full, and we have not ran it much but I do believe it is using oil. After the water pump was replaced we took it to the lake and ran it down the lake and back for a 10 minute round trip with no problem. I few weeks later we go fishing and while going up the lake the buzzers start again. I do not know much about boat motors and wandering if anyone had any advice.

Possible that the water pump is out again. I had one go out again on a Merc on the second trip to the lake once. I suppose it could be a thermostat as well. I'm not sure if that motor has one but I figure it probably does.

I would make sure and mix oil with the gas as well instead of relying strictly on the reservoir until you can rule that out.

Dont know on your Merc, but my uncles 200 E-rude buzzer starting going off one time and we thought the same, water pump, come to find out it was there was a sensor that measured the air fuel mix and the sensor went bad. Boat ran great, it was just the sensor that was bad. You might check that if your motor has one ?? You here the saying "All the bells an whistles"...it be nice if they do that on boats....instead of one buzzer sound for all things, make some diffent buzzers for differnt things....Engineers.....GEES! it aint rocket science guys !!

May want to check the float in the oil reserve tank. They become soaked and settle to the bottom which can give you a low oil buzzer.

First of all I'm not a boat motor mechanic, but let me give you a little advice from past experiences. If you're like me you want to try and fix it yourself. So, if you think it's not oiling go ahead and mix oil in with your gas. Double oil it. It's easier to replace plugs than powerheads.
Next, start checking your water pump. If it is "pissing" that doesn't mean there's still not a problem. You may have a thermastat problem (sticking or clogged).
In my opinion, if you have it double oiled and it is circulating water properly and the alarm is still sounding; it's probably a sensor or other minor problem.
Good luck... we have popped a bunch of powerheads because we tried to fix them ourselves. We had a thermastat clogged in a motor and the motor continued to "piss". We double-oiled it thinking that would prevent a catastrphic failure. Wrong again!

if you have a volt ohm meter you can test your oil level sensor, set it so that it beeps when you touch the ends together, now find the connections to the oil sensor, disconect the wires and probe them if they beep you have an open in the sensor and it is bad, it should not have continuity, it should have resistance, sorry forgot to mention the oil bottle should be full when you do this, if your sensor is bad then it should make the beeper go off, I belive that is what you may have described also if you can check the temp of the water coming out of the pee hole on the moter when it is warm, to see if it is really hot, could be a bad water pump, they both use the same alarm one usually beeps the other may go continuous, hope this points you in the right direction.

I don't know what part of KY you are in, but on Hwy 68 near the McCracken/Marshall county line, there is a fellow named Jim Simpson, who fixes outboards. He used to have a business on the lake before he retired. He is the best mechanic and has the most reasonable on prices of anybody around - PM me and I will get you his phone #.