Help! 1989 Mariner 90hp Oil Alarm Won't Stop

[jack007]

I hope someone can help me out. I've had a 1989 Mariner 90hp motor for 6 years. It's run great and been very dependable each year, except for what I always thought was a wiring problem in the oil alarm box. The alarm would go off falsely in very wet and cold conditions, in high seas, and very humid conditions. Jiggling the throttle handle, passing paper or a flat object through the connections of the metal plates of the throttle, idle, and gear levers where they all enter the helm alarm box would get it to turn off. Yesterday the beeping alarm went off in dry warm weather and would not stop no matter how the box and throtle was jiggled. After checking oil level, I got it to shore as quick as possible. Engine temperature was normal, and the usual amount of smoke was in the exhaust.
I just got the boat back from expensive non engine repairs and can't afford anymore. I'd like to pre-mix. A friend told me to just disconect the purple wire from the oil sensor...of course there is no 'purple' wire. The wires at the alarm box at the helm are white pink and blue, the wires under the oil tank at the engine are white or blue. Does anyone know how I can disconnect the alarm??? Which wire? From which end? Is there any other actions I can take? Will running pre mixed gas through the engine turn the alarm off? The marina where the boat is now complains of the shrill alarm if I work on it there.

 

[saumon]

Re: Help! 1989 Mariner 90hp Oil Alarm Won't Stop

try disconnecting the wires that goes from the oil sensor to the warning module (a small black 2x2 box located at the bottom, behind the main harness). If it stop beeping, it's most likely a faulty or stuck oil sensor (cheap), to be sure it should beep again if you join the 2 wires together. If the beep stay on when the wires were disconnected, probably a bad module (not so cheap).

 

[jack007]

Re: Help! 1989 Mariner 90hp Oil Alarm Won't Stop

Thanks Saumon for your help I'm definitely making progress here I think. Here's what I did.....I disconnected the tan wire from the oil module...the beeping stopped. I reconnected it....beeping back on, and disconnected the 2 tan to blue wires between the bottom of the oil tank and the module.....the beeping stopped. So what do you and everyone think does this mean the problem is only the oil tank float or sensor and the engine is getting oil, and all else is ok??

 

[saumon]

Re: Help! 1989 Mariner 90hp Oil Alarm Won't Stop

you got it: stuck or bad float sensor! you could try removing and cleaning it. if it doesn't solve the problem, then change it. Anyway, the intermitent beep doesn't mean that the engine isn't getting oil, it simply is an indicator of a low oil level in the tank...

 

[jack007]

Re: Help! 1989 Mariner 90hp Oil Alarm Won't Stop

Thanks loads, Saumon, everything worked good. The 'other' wire, heat sensor checked out and the engine and oil are working good. Couldn't have done it without help like this from the internet, however,.......another potential disaster has occured. I guess I should say, that when the oil alarm problem started during boat operation on Sunday 6-10, my brother was using the boat. He did get off the water as soon as possible, (which would take anyone 20 minutes from the location involved, much of it in a no wake slow rpm area), for about 1/2 of that time he said he pushed in the tilt down switch on the throttle handle to help squelch the oil alarm until he could get to dock, I thought nothing of it. After working on the oil alarm problem and fixing that (as above) I took the boat out myself for a 'test' spin today (thursday) and to my shock found the motor would not go down, (it goes up fine). At first I thought I had accidentally knoced out a wire while checking the alarm module etc., then, I remembered my brothers comment. What do you think....did he burn out the tilt motor on Sunday? Is there a way to get the motor down? Should I put on the boxing gloves with him? I realize tilt motor problems may not be in your area of expertise, and maybe I should start a new thread.

 

[saumon]

Re: Help! 1989 Mariner 90hp Oil Alarm Won't Stop

If you were playing a bit with the oil sensor wire, chances are you disconnect one of the trim wire, located at the same place (been there, done that). First of all, check if the trim swith located on the cowling is working both ways. If so, you just need to reconnect tightly the green/white wire that goes from the main harness to the control. There should be a bullet-style connector located somewhere under the oil tank or under the fuel pump. If it doesn't go down with the cowling swith, it's most likely a dead trim relay. Let us know what's happenig.