1991 40 "Classic" Buzzer/alarm wont shut off.

[Schtoopid]

So, had my boat out for its maiden voyage today.
Ran great for a while, I shut down for a bit, and when I tried to start, the warning buzzer wouldn't stop.
Disconnected the sensor wire on the "head" of the cylinder (water jacket near plugs) No change.
Disconnected the oil float level alarm.. No change.
Shorted the oil float level sender.. Alarm "warbles"

So, what other sensor is there that would have the alarm going off?

 

[Texasmark]

I had an answer prepared till you said that you shorted out the oil sensor and it "warbled". Apparently you have a modulation module in your engine that modulates the oil signal for one to determine what is at fault when getting an alarm. For the alarm to sound, the engine has to provide a "ground"....a short circuit back to the battery - terminal....usually occurring at the engine block for engine internal wiring.

Since you were able to make the distinction, to me there is only one solution. The modulation module has to be defective. If you can't find it, it has red and black for power and tan for heat and blue/white for oil wires in the attached connector. Guessing it's black and about 1 to 1 ?" square.

Pull the plug to it and see if your problem stops with your removed test connections put back in their proper places.

I just realized that you are talking about the 4 cyl engine. I am not familiar with how that engine is connected up for oil injection. If the engine has an oil tank under the coil then I'd assume you have a modulation module with the condition you described. Otherwise I don't know.

 

[Schtoopid]

Yeah, solution was hit the alarm box with a wrench.. Then it stops..
Unfortunately, its one of those damn epoxied boxes.. No way to fix it, and I'm not spending any more money on a 25y old worn out 40hp.... So now its disconnected.

 

[Texasmark]

If you are worried about not having it, disable your oiler and run 50:1 (gas to oil ratio....6 gal to 1 pt ) in your fuel tank.

 

[Schtoopid]

Texas - Thats what I've done. Oiler wasn't working, so I bypassed it and I'm just running mixed. Runs MUCH better and no longer behaves like a POS.