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1999 4.3L Mercruiser alarm beeps repetely with motor running even with full oils and low temp?

D

Dave Johnson2

New member
I have a 1999 Bayliner Capri with the original motor, a 1999 4.3L Mercrusier inboard/outboard. When you turn the key to the on position it has a loud, long continus beep until the boat starts and then the alarm is silent(this is normal operation, it has always worked this way).

The other day, I was out on the water(alarm was silent) The boat was running great as usual(this motor never has any issues, always starts on one crank and runs very strong and quiet), then the alarm came on, luckily I could still see the dock so I just pulled the boat out of the water and checked the oil in the motor, it was low. I topped off the oil and put the boat back in the following day and herd the same loud, long continus beep until the boat starts(normal) but as soon as the boat started it starts beeping repetely with the engine running. This beep is no where near as loud as the loud, long continus beep the alarm makes with the ignition/key in the "on" position and it beeps regularly every 1-3 seconds...Beep......Beep......Beep........Beep.......Beep. So I checked the oil dip stick and it was at the full line)because I just topped it off yesterday) I checked the drive oil resorvoir and it was at the full line and the boat had only been on for 1 minute so it was not over heating but the alarm was still beeping. I am confused? Why would the alarm beep with the motor running if both oil levels are full and the temp is low? (The oil pressure is about 40 when ideling and may go up to 60 when crusing fast).

Since oil levels were full and temp was low, I figured I would not cause damage to the motor by letting it run for a bit. I let it run for a bit hoping the beeping would stop(I was hopeing/guessing it would level out/fix its self sine oil was now full)but it just keept beeping for like 20mins. I would start and stop the motor but it just kept beeping. Again I turned it off and started it up and the beep was gone! I was so happy and let it run for 20min with no beeping. Then I cut it off again and started it up and it was beeping again. I did this all at idel for under a hour and got it to not beep twice for a bit, but the beep would always come back. I gave up for the day and came back the follwing day and stated the motor and cut it off then start it again(all anchored down at idel) and it always kept beeping while the motor was running, at this point it seems to always beep every 2 seconds while it is running.

I understand I can unplug the 2 wires under the drive oil resorvoir with the boat running and it that stops it, then its the float in the drive oil resorvior and I will need to replace the drive oil resorvior and that should fix/stop the beep.
Heres my question:
What if unplugging the 2 wires coming out of the bottom of the drive oil resorvoir does not stop the beep? what should I check next? I understand there are some type of sensors for the motor oil level and for the temperture but I dont know where they are located or how to test them?

Thanks in advance for your input...
 
I am not sure which one it is but I do know the serial number:

Engine Serial Number: OL096958
Engine Model Number:4-211015LS

Any advise would be greatly appreciated, thanks so much
 
The steady buzzer sound with the key on suggests it is carbed; not efi. Also the engine serial no. looks like it is pre-EFI.
(You should look on your engine data plate or maybe the plastic top cover for any indication of MPI or EFI.)
The intermittent buzzing while running suggests that it may be a soft alarm set by an EFI module. So it is kind of confusing.

The four alarm points typical for a carbed engine are: low oil pressure, high temperature, low drive oil level, and sometimes low cooling water pressure.
Your can test each one separately by unhooking the sensor.
The temp sensor is located on top in front on the T'stat housing.
The low oil press sensor is located on the port side low towards the back, just above the oil filter.
The low water press sensor will be located on the inlet water line somewhere between the transom assembly and the T'stat housing.
You know where the drive oil level switch is located.
Each should connect to a tan/blue colored wire.
Do not undo any connectors that are any other colored wire, and remember to reconnect any that you undo.
If disconnecting one of them stops the buzzer, that is your bad sensor.
If you cant locate these sensors, you will need to get a service manual or visit a boat shop.

If you install a new sensor and the intermittent buzzing continues, then that points to a more serious problem.
If your oil pressure gauge reads normal, and it is still cool after just starting up, that would lead you to suspect a bad drive oil level switch or a problem with your cooling water press switch, if equipped. You may have picked up some trash in your water pump. When was the pump impeller last relaced? They should be done every 5 years or 250 hours at least.

Hope that helps,
Rod
 
Rod,
Don't know how I missed your post about 10 mins. before mine, but looking at that post and a few others you have made show your a true professional.
Thank you for taking the time to explain things .
 
gl115 said:
Rod,
Don't know how I missed your post about 10 mins. before mine, but looking at that post and a few others you have made show your a true professional.
Thank you for taking the time to explain things .
Click to expand...

gl115; Thanks for the kind words. Just trying to help others out when I think I might have something helpful to offer.
Boats are llike lots of other things; people helping people. There are many other regulars on the forum who are much more knowledgable than I am.

Best regards,
Rod
 
Hi!
Need help with a Mercruiser 4,3 MPI from 2008. A strange intermittent alarm after 3500 rpm but gets silent again if I reduce the throttle, see video link below. Is this the same problem as described above?

I've installed new water pump and fuel pump, impeller and thermostat. I have checked the oil and gas filters, the ignition box, spark plugs and no water in the fuel.
I plugged the computer box and searched for error codes, but nothing came up.


Any thoughts or clues would be much appreciated!

 
Crappy video...................more focus on the gauges for a longer period of time would be better.

Also videoing the wake does not help anything.

Try again...............
 
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