So, when I was out yesterday my boat started to make random beeping noises while on plane.

It was random, like it would short beep. Stop for a few minutes. Short beep again. Stop for but. Short beep. No time-frames between the beeps.

At first I thought it was the depth alarm on the Lowrance going off, but when I turned the depth finder off, it kept beeping.

Engine seems to be running fine. Water is coming from the outboard like normal.

No issues out of the ordinary, the Outboard usually takes one or two tries to fire up. But, it's done that since I've had it.

2003 Mercury 115HP two-stroke.

LOW OIL LEVEL: The low oil level warning is activate when the remaining oil in the mounted oil resevoir tank drops below 50 fl. oz.... WARNING HORN EMITS A SERIES OF FOUR BEEPS.

ENGINE OVERHEAT: HORN SOUNDS CONTINUOUSLY

ENGINE OVERSPEED: INTERMITTENT BEEP until engine speed drops below MAXIMUM RPM.

ELECTRICAL SENSOR NOT FUNCTIONING: If the TPS, MAP, or CTS is not functioning, or is out of it's "pre-programmed diagnostic range", the warning horn will sound INTERMITTENTLY.

WATER IN FUEL WARNING: SERIES OF FOUR BEEPS.

Thanks for the info Muzzlebreak.

I'll have to monitor the beeps better next time I go out. The water was very, very choppy. So, I'm not really sure what it was

The beeps weren't coordinated in any specific pattern.

That's great info for me about the beeps!!

I have a 2001 V18 w/Merc 90hp and it does that when the oil reservoir is getting low (about a 1/3 full). It especially does it when it's just starting to get low and I'm running across the lake when it's choppy.

I had a similar issue earlier this year... Boat was running great, but the beeping was coming & going with no pattern to it! Turned out to be a faulty tachometer. Got a new one & everything is great again! Unplug the tach & see if it stops beeping...

Thanks for the info! Seriously, the MOST helpful forum I've been a part of.

I'll check the oil when I get home today, it could be that because the water was very choppy and it only seemed to go off when I hit a big wave.

The tachometer doesn't function so it could be that as well. I'll try one at a time and see if it improves.

Thank you so much!!

Float in oil tank is failing more than likely only 2 warnings on that motor oil and heat.

I'm pretty confident it was the oil sensor going off intermittently because of the choppy water and bouncing around a lot.

The oil was less than 1/3, not enough for a low oil warning, but the magnet float could have easily been hopping around in there with the chop. That would explain the really weird and untimed beeps.

I'ma fill her up before I go out this weekend and report back.

+1 same thing on my 175. Replaced cap and it quit. Takes those beeps seriously and check hose connections. Loose connection at remote tank just cost me a motor. Doubt you do but if you have quick connect at remote tank replace with one that has nipples for hose connections.

Alrighty, I was really low on oil. Not low enough for the sensor to go off, but I was almost there. Filled the oil tank up and took her out. Absolutely no beeping.

Also did some look-over maintenance while I had the cowl off. Everything is clean and looks pretty much brand new. Plugs are good, compression is awesome and all the connections and nuts are still tight.

Engine looks damn good for 14 years old.

Thanks for the help!