96 Mariner 150EFI fast beeping sound while engine is running

Went to the lake this evening and while on the way back to the ramp my beeper started beeping really fast...like a beep beep beep. I was running it pretty hard and it had been running probably 5 minutes before it started making the beeping. As soon as I heard it I shut it down immediately and trolled back to the ramp with trolling motor. I used the engine to put the best on the trailer which took probably 30seconds max and it was still beaping. Any suggestions to what possible causes might be would really be appreciated thanks.

Low ooil level in the day tank mounted on the engine. Need tofind the air leak or plugged filter causing the problem.... If it is an efi engine the water seperating fuel filter is full of water which will also set off the lite on the box mounted on the bottom of the ecu to start blinking along with the horn. U more than likely did not hurt the engine running it after the horn went off!!!

[quote=boatwhisperer]Low ooil level in the day tank mounted on the engine. [quote]

check motor tank cap and float switch also.. its notorious for crackin' and/or float switch goin' south..

If the motor mounted oil reservoir is low, likely that the main oil tank screen needs cleaned. It is on the bottom of the oil line side.

Thanks guys!...I will look at that stuff and see what I can find

Checked my float and oil level in both tanks...level in the main tank is about 1/4 and the reservoir was full. Cranked it this morning with water hose connected and as soon as engine cranks buzzer is going off....8f it means anything the little box on the engine that has the little red light doesn't flash or do anything.....about to get more oil and mix in the fuel tank just for a precaution while messing with it. Any more ideas before I take it to boat shop?

Sounds like the oil pump drive gear.

did ya "check" tha switch in tha cap or did ya jus look for tha "full" tank? it can be bad even if tha "float" moves up n down......

either disconnect it with it powered or check with an "ohm meter"...

Just run it till it blows.. Collect insurance on it.

Like TLW said with buzzer sounding, disconnect the ground wire going to the oil reservoir cap to check it (buzzer stops that's it) and same on the rotation sensor

I have the 200 96 mariner efi and the wires on the cap were my issue when that started happening.

Had almost exact same issue with my Mercury 150 EFI yesterday. Full oil reservoir both on top of motor and storage. Found oil on the side of the cowling where the hose from the tank connects to the brass fitting that leads to the short hose to the tank on top of motor...so know I have an oil leak there. Cut zip tie and hose easily slid off fitting. Cut an inch off it and re-attached it. Hooked it up to muffs and no more beeping. How do I check the wires at the top of the cap? And does it plug into the front bottom of the motor? That was unplugged when I found it the other day. Wonder if the previous owner just unplugged it because it was beeping and he knew switch was bad? Compression is good on motor...

Checked top oil tank...was only half full. Added oil since I had the leak to bleed air out. All seems to be ok now.