Oil Alarm problem on 115 hp 4cyl 2-stroke

billc_sbio

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Oct 24, 2008
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O.k., here's my problem...I have a '91 115 hp Merc 2 Stroke with very low hours on it.

On my most recent outting, we were out fishing and on the anchor, shut down.

We hooked fish, two times, and dropped back downriver with them, fired up the big motor to come back upriver to get back on the hook. Each time, no problem with the motor or any alarms.

Then, while hanging on the hook I reached over and toggled the motor trim/lift switch (which I rarely ever use do to the fact that the motor is jet pump equipped and it never needs to be moved). Probably due to non-use/dirty contacts, the motor didn't budge, the solenoid/s just "clicked".

Then, upon firing up the big motor to return to the launch, the Oil Alarm Horn went off and sounded beeping continously.

I don't think there's a "real" (oiling/delivery) problem as the Oil Tank's full. However I shut down the motor and used the kicker to return to the launch.

I believe that by toggling the Motor Trim Switch I initiated this Alarm or even possibly "popped" something electrical, which caused this to happen.

I was going to buy one of the common Mercury O.B. Repair Manuals to help troubleshoot this, but while reading reader's reviews on a major one, one of the reviewers stated he had an almost identical problem and the manual didn't address the issue in enough detail to effect a repair or troubleshoot. He said he resolved it by going to online forums, so here I am.

Is there anyway to "Reset" this alarm?

In lieu of that what methods must be used to Troubleshoot for my problem?

Again, I think the actual problem is just the Alarm (sensor) itself.

Thanks,
Bill C.
 

Laddies

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12,218
Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

A continual horn it heat not oil, if thats the case go to the water jacket cover and disconnect the tan sender wire and if the horn stops the sender is bad if not you have a shorted wire.
 

krakatoa

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Aug 8, 2008
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705
Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

Laddies are right, but if you have any chance grab the service manual for your engine, I assure you will learn a lot :D of things regarding your 115 HP.
 

billc_sbio

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Oct 24, 2008
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Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

A continual horn it heat not oil, if thats the case go to the water jacket cover and disconnect the tan sender wire and if the horn stops the sender is bad if not you have a shorted wire.

Well...not "continual" horn, but continuous BEEPING horn.

Plus the motor wasn't warm when fired up from cold start.
 

Laddies

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Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

Then, upon firing up the big motor to return to the launch, the Oil Alarm Horn went off and sounded beeping continously.

This says continously, so much for that. The oil sender is for low oil only so unplug the 2 blue wires from the bottom of the oil tank, if the horn stops then the tank needs to be replaced as the magnet has fallen off the float. If it don't stop there is a wire shorted.
 

billc_sbio

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Oct 24, 2008
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Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

Then, upon firing up the big motor to return to the launch, the Oil Alarm Horn went off and sounded beeping continously.

This says continously, so much for that. The oil sender is for low oil only so unplug the 2 blue wires from the bottom of the oil tank, if the horn stops then the tank needs to be replaced as the magnet has fallen off the float. If it don't stop there is a wire shorted.

O.k., thanks for this info.

Also does this, Continous Beeping Alarm, ONLY indicate "Low Oil" (and not an Oil Delivery problem)?

Some have said (and I certainly wouldn't disagree) that it WOULD help if I had good Service Manual (for this, and other issues in the future).

But then I've read that so many manuals out are so "generic", covering so many (too many?) models all at once as to be not all that useful.

So WHAT Manual would be a "good one" for this series of motors?
 

Laddies

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Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

The beeping is for low oil only not a oil delivery problem your system does not have a warning for that. Nice Huh. Intermittent beeping can only be caused by the magnet falling off or the oil module has failed. If you buy a manual, bit the bullet and get a Mercury manual.
 

billc_sbio

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Oct 24, 2008
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Re: Oil Alarm problem on 115 hp 4cyl 2-stroke

Hehe Laddies,

Thanks much for your valuable advice.

Looks like it'll be an OEM Manual, makes sense to me.

Thanks again.
 
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