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.