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Need Help Identifying A Mercruiser 4.3L Component (Sensor / Switch)

jimn said:
The engine/drive manufacturer isn't usually the source of the alarm buzzer, that's usually part of the harness installed by the boat manufacturer and they usually put it under the helm. It's often similar to the part in the photo- doesn't matter if it looks the same as long as it does the job. It's usually a piezoelectric buzzer.

Don't be too surprised if it has been removed, a wire has been cut or it has been covered with tape- I have seen those on boats and read recommendations to cut the wire on a boat user forum.
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Thanks @jimn, you were correct and found the alarm lurking under the dashboard. It's been completely disconnected, so the alarm will never sound...

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_jp said:
Thanks @jimn, you were correct and found the alarm lurking under the dashboard. It's been completely disconnected, so the alarm will never sound...

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Cool. I worked on a boat that had the wire disconnected, by the boat owner. It was a Regal Rush with 90HP Mercury jet drive and he cut it because he didn't like the sound but that was supposed to tell him that the 2 cycle oil reservoir was empty, so he scattered the powerhead. Good sized holes in the sides, connecting rod parts, roller bearing parts, linkage and oil all over the engine compartment. He didn't like the quote for the repair so he complained to the right people and even though he did it intentionally, the covered the cost of the powerhead. He didn't like the labor bill, but he screwed us out of the money for the parts, so.....
 
I connected the alarm back up today and it sounded as soon as the ignition was activated - constant. I presume that's why the previous owner disconnected it, rather than finding the problem. Or is it supposed to do that? Before I go looking for a problem that doesn't exist :unsure: lol
 
It is suposed to do that. No oil pressure.

I say buy an alarm that makes a likeable sound....lol Maybe a womans voice say "Hello Captain"...
 
Many times accessories such as stereos may be wired to only work with key in run postion. Most boat key switches dont have a Acc location for this purpose. They are typically Off/RUN/CRANK only
 
Thanks @kghost, I really wasn't expecting it to sound straight away - as long as that is correct then that's ok. I might look at installing a short time delay device, giving enough time to start the engine before it's activated. Or having it only operate in the run position would be good.
 
_jp said:
.... Or having it only operate in the run position would be good.
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That's the way the horn is powered, if its in the factory wiring configuration.

Personally, I prefer no delay in activating the horn when the key is turned...It provides a check on the warning horn and validates the oil pressure switch - not perfect but cost effective. I have seen way more oil pressure switch failures than overheat or gear level switch failures (which is intuitive) so I belive it to be of benfit.
 
makomark said:
That's the way the horn is powered, if its in the factory wiring configuration.

Personally, I prefer no delay in activating the horn when the key is turned...It provides a check on the warning horn and validates the oil pressure switch - not perfect but cost effective. I have seen way more oil pressure switch failures than overheat or gear level switch failures (which is intuitive) so I belive it to be of benfit.
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Maybe it's something i'll get used to. Or put a light on it instead lol
 
My opinion only.

The fuel pump has a oil pressure switch to shut pump off if no oil pressure.

That being said and its your final decision but I would simply disconnect the oil pressure alarm sender wire and tape off and alarm will no longer activate when key is in the run position.

Millions of boats manufactured prior to alarm systems were used has NO alarms at all. We used our gauges to see what is giong on with engine. My 1987 mercruiser has NO alarms...
 
kghost said:
My opinion only.

The fuel pump has a oil pressure switch to shut pump off if no oil pressure.

That being said and its your final decision but I would simply disconnect the oil pressure alarm sender wire and tape off and alarm will no longer activate when key is in the run position.

Millions of boats manufactured prior to alarm systems were used has NO alarms at all. We used our gauges to see what is giong on with engine. My 1987 mercruiser has NO alarms...
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I'll see how annoying I find it when out on the water - I will most likely modify it some way or another. Thanks for the input
 
_jp said:
Thanks @kghost, I really wasn't expecting it to sound straight away - as long as that is correct then that's ok. I might look at installing a short time delay device, giving enough time to start the engine before it's activated. Or having it only operate in the run position would be good.
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Buzzers with variable output used to be available- not sure if they are now. They had a disc that could be rotated and it would partially close the opening, to reduce the sound. Some people put tape over the hole, but that makes it hard to hear when under way.

If you don't have ideas for the delay device, look for a 'pulse stretcher'- they were used for delaying power ampolifier turn on when I was doing car audio.
 
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