1998 mercury 200 efi alarm going off and on

[Stormiepete]

We have a 1998 mercury 200 EFI and when out on water we get a steady horn buzz, but then for no reason will start back again with no rhyme or reason. No special timing or any certain condition . Usuall after being on water and motor running less than 30 mins. We do see the 2 cycle smoke sometimes more smoke than others and we get a steady stream of water out the weep hole. Oil reservoir at motor is full and plenty oil in remote tank. Alarm does not go off sitting in driveway running motor. I do not have a lot of experience on boat motors. Any advice or input on this would be greatly appreciated based on descriptions of happenings.

Thanks in advance

 

[Faztbullet]

Check the fuel filter for water as it has a sensor in bottom of it.

 

[wn6ngp]

A common problem that I have observed is an intermittent oil level switch inside the tank on the motor. I've heard that over time oil will dissolve the adhesive holding the switch in place . Unfortunately, the solution may be a new tank, yours might be different. To diagnose this find out where the connector is for that sensor, disconnect and then see what it takes to make the alarm go off. Unfortunately, I can't remember if the low oil warning switch is normally open or closed so you will have to google or experiment to figure that out.

 

[Dukedog]

normally open....

only "steady, continuous beep" is over heat... all other, ie: oilier or water in fuel related is gonna be an oscillating beep, beep..... oem water pump "kit" is first thing done with unknown over heat warning no mater what pee stream and pump parts actually look like.......... jmo