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Buzzer going off on my 1996 115 outboard Mariner

S

Scooter D

New member
I bought a boat from a co-worker that was having trouble from the buzzer going off. He had the auto oiler removed with Murcury parts and started mixing the oil with the gas. The buzzer is still going off. After buying the boat i took it out for the first time myself, after unloading and not getting out of the no wake the buzzer would beep, go off at times, and studder off on. Thinking the buzzer may be bad, i ordered a new one and replaced it. When backing it off the trailer and giving it some throttle, the buzzer sounded continuously. I loaded it back up and headed home. I took the hood off and did notice a wire was diconnected guessing where he had the oiler removed. The motor is peeing and besides it didnt run 5 minutes before loading back up. Does anyone have any help? Thanks.
 
I'm definitely no expert but I had to mess with the oil warning circuit a bit on my 1997 115hp. I'd be checking for one of the wires to be shorted to ground somewhere, or for a bad low oil sensor, oil warning module, or temperature sensor. The Tan/Blue wire goes from the harness connector to the oil warning module and the temperature sensor. If that wire gets grounded I believe it makes the buzzer sound. I attached a picture of of the wiring diagram for your motor below. Yours might not have the rpm limiter if it didn't come with a jet drive but the alarm circuit should be the same.
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Mercury-Mariner, don't know the differences other than color, decals, and country of origin...US/Belgium vs Japan.

On/in the Mercury engine you have a tan/blue strip wire on Pin 3 in the 8 pin wiring harness to the control box and helm station. If you ground that wire, and have the key somewhere other than off, you will have applied 12v across the warning device...horn and it sounds, and if a dash light is connected at the helm station pigtail, it will illuminate.

In the engine ground comes from 3 sources: (1)OT switch on the rear of the block, buried in the water jacket cover, lower left corner, tan wire. (2) Oil level in the oil tank blue wires, shorted to ground if oil level is low. If tank is removed, then the blue wire pigtailing in the engine side of the engine to remote 8 pin connection should be removed from the multiple pigtail.....which also contains the OT signal mentioned. (3) on some engines, a modulation module is installed and it gets the warning signals but modulates the oil alarm to a 10101010 rather than a 0 (solid ground) to identify the source of the alarm as oil level related.

The wiring diagram for 1996 year-model Mercury engines shows a module to be installed. The blue wires from the tank enter and a tan wire exits to a terminal block where the OT tan wire is also located in parallel.....either signal therefore will determine the ground (or not) configuration of the output wire of that junction block which is a tan/lt blue striped wire going to the engine side of Pin 3 of the 8 pin remote connector.

On what the removal process you described i have no idea, but grounding of pin 3, however that is accomplished will blow the horn.

The OT sensor is normally open circuited. At about 195F it closes and grounds the low side of the horn. If your oil tank removal action removed the blue wires feeding pin 3, then the only thing feeding Pin 3 is OT alarm and you must have a malfunctioning OT sensor switch, or a very real OT problem.

Tell Tale water from that engine comes from the exhaust water jacket......follow the hose, not the block internal and is NOT controlled by the thermostat nor higher rpm Pop Off valve. Therefore you could have a thermostat sticking shut, or a stuck Pop Off causing an over heat condition with the Pee being somewhat warm.
 
Texasmark said:
Mercury-Mariner, don't know the differences other than color, decals, and country of origin...US/Belgium vs Japan.

On/in the Mercury engine you have a tan/blue strip wire on Pin 3 in the 8 pin wiring harness to the control box and helm station. If you ground that wire, and have the key somewhere other than off, you will have applied 12v across the warning device...horn and it sounds, and if a dash light is connected at the helm station pigtail, it will illuminate.

In the engine ground comes from 3 sources: (1)OT switch on the rear of the block, buried in the water jacket cover, lower left corner, tan wire. (2) Oil level in the oil tank blue wires, shorted to ground if oil level is low. If tank is removed, then the blue wire pigtailing in the engine side of the engine to remote 8 pin connection should be removed from the multiple pigtail.....which also contains the OT signal mentioned. (3) on some engines, a modulation module is installed and it gets the warning signals but modulates the oil alarm to a 10101010 rather than a 0 (solid ground) to identify the source of the alarm as oil level related.

The wiring diagram for 1996 year-model Mercury engines shows a module to be installed. The blue wires from the tank enter and a tan wire exits to a terminal block where the OT tan wire is also located in parallel.....either signal therefore will determine the ground (or not) configuration of the output wire of that junction block which is a tan/lt blue striped wire going to the engine side of Pin 3 of the 8 pin remote connector.

On what the removal process you described i have no idea, but grounding of pin 3, however that is accomplished will blow the horn.

The OT sensor is normally open circuited. At about 195F it closes and grounds the low side of the horn. If your oil tank removal action removed the blue wires feeding pin 3, then the only thing feeding Pin 3 is OT alarm and you must have a malfunctioning OT sensor switch, or a very real OT problem.

Tell Tale water from that engine comes from the exhaust water jacket......follow the hose, not the block internal and is NOT controlled by the thermostat nor higher rpm Pop Off valve. Therefore you could have a thermostat sticking shut, or a stuck Pop Off causing an over heat condition with the Pee being somewhat warm.
Click to expand...

I tried to take it out yesterday but the new buzzer sounded before i backed it off the trailer so loaded it back up and headed home. I took the hood off and found a black ground wire wire broken off one of the coils that lead to one of the spark plugs. I crimped a new end on and reconnected. Put the muffs on and now the buzzer sounds continuous with the first click of the key. I dont think heating could be the issue, it didnt run 5 minutes before loading back up and engine not running after i returned home? As i stated the oiled was removed. There is a tan wire from the harness that is unhooked along with 2 blue wires assuming they went to the oiler that was removed. The only thing that was done to this boat is that the oiler being removed. Has to be something simple???
 
Some outboards have a sensor in the oil pump. If the pump is not spinning, it sends ground to module. If the oil tank was removed, the blue wires are not needed. Is there a sensor on your oil pump?
Make sure the removed ends are not able to touch a ground. Find the over Temp sensor at the top of engine. When the alarm goes off.. unhook the wire. If the alarm stops. The OT is sending the ground. The only thing the alarm needs to do is make a sound. If it makes sound it is working.
 
I found a black wire pinched behind the harness connector at the engine. I cut this wire and the buzzer does not sound. Touching this wire to the teminal block sounds the buzzer. This wire comes from the oil warning module. Can this oil warni g module be removed??
 
The alarm has 2 inputs which ground the low side of the alarm. One is the oil level. One wire goes to the unit and an identical wire goes to engine ground. If the oil is too low the float switch on the inside of the fuel tank closes and puts ground on the output wire. If your engine has a warning module, this tank output wire goes to the module as an input. The output goes to the tan/light blue wire, pin 3 of the warning harness and cuses a 101010 alarm.

If I understand what you said, the "input" wire to the module was pinched under the module, shorting to ground. This would cause a solid alarm and yes it would be immediately upon your turning the ignition switch to ON which supplied 12v to the horn.
 
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