Alarm Sounds when batteries switched on and no key in ignition

[cabrio777]

We have a 2012 Larson Cabrio 777 with a 5.0 mercruiser and bravo 3 leg
I Have just had the motor and leg serviced during winter. was a major service including manifolds and risers. And the leg was sent to a specialist for recon.
after all the work has been completed. Now i have a constant alarm sounding when the batteries are switched on. The motor starts perfectly and runs great and the oil reservoirs are full. We have disconnected the gear oil sensor to eliminate that alarm.
Our mechanic suggests that its another sensor somewhere the only way to stop it is switch off the batteries.
Does anyone know if the batteries arn't fully charged will the system alarm
cheers

 

[fatlenny]

ummmmm, I am unsure about the battery charge level question but Let me make sure I understand.
You just had a bunch of work done including the drive leg serviced. You have an alarm that continues to go off until you disconnect the gear oil sensor that should have been some part of this service done. I assume that this was all done by the mechanic you mentioned other than the work that was sent out. If this is accurate and your mechanic is not working to correct the issue back to a correct working order via working on it himself or contacting the outside vendor, I would be getting a new mechanic at the least. I dont understand how this issue wasnt noted and reported to you during the end of the service job because one would have to believe if it was delivered to you in this condition, it was doing it on the start up any mechanic would have done when the job was completed.

I would hate to throw money at an issue that arrived after I paid someone to work on something so I would start with making sure batteries are all on a full charge and check the wiring harness to ensure that something wasnt left unplugged and or damaged during the work. look for any pinched or cut wires. If all is good there the next step I would be doing is replacing the the sensor you are disconnecting to make the alarm stop. If all fluids are good, (check at lower unit as well,) and the alarm is going off, the sensor failing would be my guess.

 

[Scott Danforth]

check that your gear oil sensor isnt gummed up. use a DVM

the mercruiser oil has additives that drop out of suspension and gum up the float sswitch. remove the reservoir. empty the reservoir, use appropriate cleaner (carb cleaner, mineral spirits, diesel fuel, etc)

do not try to disassemble the switch from the reservoir. its a one-time assembly thing.

then check the float with a DVM
replace the reservoir
then refill

then get a new mechanic, because every marine mechanic worth anything would have troubleshot the alarm, and fixed it prior to returning the boat to you

 

[alldodge]

Just to clarify
Alarm comes on when Bat switch is turned ON and the key is OFF (motor not running)?

 

[Grub54891]

I've cleaned lots of those gear oil reservoirs over the years. Problem solved. When servicing the lower unit, the reservoirs sometimes will empty and then the float will drop down into the sludge, It stays there till cleaned.

 

[cabrio777]

ummmmm, I am unsure about the battery charge level question but Let me make sure I understand.
You just had a bunch of work done including the drive leg serviced. You have an alarm that continues to go off until you disconnect the gear oil sensor that should have been some part of this service done. I assume that this was all done by the mechanic you mentioned other than the work that was sent out. If this is accurate and your mechanic is not working to correct the issue back to a correct working order via working on it himself or contacting the outside vendor, I would be getting a new mechanic at the least. I dont understand how this issue wasnt noted and reported to you during the end of the service job because one would have to believe if it was delivered to you in this condition, it was doing it on the start up any mechanic would have done when the job was completed.

I would hate to throw money at an issue that arrived after I paid someone to work on something so I would start with making sure batteries are all on a full charge and check the wiring harness to ensure that something wasnt left unplugged and or damaged during the work. look for any pinched or cut wires. If all is good there the next step I would be doing is replacing the the sensor you are disconnecting to make the alarm stop. If all fluids are good, (check at lower unit as well,) and the alarm is going off, the sensor failing would be my guess.

No we permanently disconnect the gear oil sensor to eliminate disable that alarm
And the alarm goes off regardless of the gear oil sensor
The gear oil sensor onl activates if the ignition is ON
This alarm activates with no key in ignition at all
And only the battery switch in pm position

 

[alldodge]

ok, someone connected a wire in the wrong place.

Look for purple wires on the motor harness and pink wires on the EFI harness. Somehow the power is being applied

If the Main Power Relay (MPR) has a ground being applied from ECM side, then when Bat is connected it will send power through out. Pull the MPR (will have Red/Pur wires connected) and see if alarm stops

 

[cabrio777]

ok, someone connected a wire in the wrong place.

Look for purple wires on the motor harness and pink wires on the EFI harness. Somehow the power is being applied

If the Main Power Relay (MPR) has a ground being applied from ECM side, then when Bat is connected it will send power through out. Pull the MPR (will have Red/Pur wires connected) and see if alarm stops

I will look but wouldn't the harness only connect one way. There would be no reason to alter the wire positions in the Junction connector
There were no alarms after full service but then had the leg removed and sent away for repair as wasn't selecting gear properly
After reinstall leg now have constant alarm even when key is in my pocket
It's not

 

[alldodge]

Agree, wiring shouldn't have changed, but something is wrong

Start with pulling the MPR

 

[tank1949]

Take sensors out of the loop one at a time. I disconnected my reservoir due to crud. I cleaned out crude and reconnected.

 

[dingbat]

The alarm system typically isn't armed until powered through the key.

I would be looking for a ground loop related to the drive.

Doesn't have a Mercathode by chance?

 

[cabrio777]

The alarm system typically isn't armed until powered through the key.

I would be looking for a ground loop related to the drive.

Doesn't have a Mercathode by chance?

Yep and I had gave the leg a coat of paint and just read the manual says don't do that

 

[Fun Times]

Yep and I had gave the leg a coat of paint and just read the manual says don't do that

Is your engine model fuel injected or carbureted?
Engine serial number handy?

 

[alldodge]

Yep and I had gave the leg a coat of paint and just read the manual says don't do that

The Mercathode anode is at the bottom of the transom plate. If it's there its covering the trim line manifold

 

[cabrio777]

Just to clarify
Alarm comes on when Bat switch is turned ON and the key is OFF (motor not running)?

Yes no key in ignition

 

[cabrio777]

ok, someone connected a wire in the wrong place.

Look for purple wires on the motor harness and pink wires on the EFI harness. Somehow the power is being applied

If the Main Power Relay (MPR) has a ground being applied from ECM side, then when Bat is connected it will send power through out. Pull the MPR (will have Red/Pur wires connected) and see if alarm stops

Did that no change

 

[alldodge]

Pull MPR and take a volt meter and trace where the power is coming from

 

[tank1949]

Did that no change

Somewhere + is getting to alarm. Back track!!!!!!

 

[cabrio777]

Found the issue
Had checks done by electrician and found the Rule float switch was the issue
Replaced and all good

 

[cabrio777]

Thanks to all the advice received helped a lot to sorting out the issue