Yanmar 2GM Alarm Question

[pateco]

Went out sailing yesterday, and motoring out everything was fine. Once we got the sails up, I went to shut the engine off, and instantly got an alarm from my panel.

Example of Panel (Not Mine) Mine looks a lot more worn than this.

This alarm would not shut off even when removing the ignition key. Worried, I restarted the engine, and the alarm stopped. I then tried to shut down again, and the alarm came back. Not wanting to sail with a blaring alarm, we motor sailed for a short time, while I started getting paranoid about the alarm. When the paranoia took over, I decided not to press my luck, and we dropped sails and headed back to our Dock. She motored fine the whole way in, but I noticed at higher RPMs the charge warning lamp on the panel would come on. At lower RPMs the charge lamp went out.

When I killed the engine after tying up at our dock, the alarm did not go on.

So now I don't know where to start to diagnose this issue. Any insights or suggestions would be greatly appreciated.

 

[Charles Erwin]

The buzzer and the charge lamp have 12v + when the key switch is on. They illuminate or buzz when 12v - is present on the other side of the circuit. In the case of the charge lamp 12v - occurs when the alternator stops turning. This will also happen if the charge lamp wire came loose and contacts the motor block.

If the key switch is off it is not possible for the lamp or buzzer to work because there is no 12v + source. If the lamp and the buzzer work with the key switch off then the key switch is faulty or a wire is loose and has come in contact the 12v+ supply at the panel. In short - 12v+ is available to the lamp and buzzer at key off and it is not supposed to be.

It is possible the test switch - marked "check" in your photo - is faulty. This switch provides 12v - to the lamp and buzzer so you can verify the overheat and low oil pressure lamp and buzzer work. If it is faulty - then the lamp and buzzer will work when the test switch is off, however these circuits still need to have 12v + present.

Long distance diagnosis is not very reliable - but it seems there is one or more problems with the panel wiring. Possibly loose wires on the backside of the panel. Check for a loose wire at the alternator and where the senders are threaded into the motor - Oh - and check for any possible wire insulation chafe too.

Charles

 

[pateco]

The buzzer and the charge lamp have 12v + when the key switch is on. They illuminate or buzz when 12v - is present on the other side of the circuit. In the case of the charge lamp 12v - occurs when the alternator stops turning. This will also happen if the charge lamp wire came loose and contacts the motor block.

If the key switch is off it is not possible for the lamp or buzzer to work because there is no 12v + source. If the lamp and the buzzer work with the key switch off then the key switch is faulty or a wire is loose and has come in contact the 12v+ supply at the panel. In short - 12v+ is available to the lamp and buzzer at key off and it is not supposed to be.

It is possible the test switch - marked "check" in your photo - is faulty. This switch provides 12v - to the lamp and buzzer so you can verify the overheat and low oil pressure lamp and buzzer work. If it is faulty - then the lamp and buzzer will work when the test switch is off, however these circuits still need to have 12v + present.

Long distance diagnosis is not very reliable - but it seems there is one or more problems with the panel wiring. Possibly loose wires on the backside of the panel. Check for a loose wire at the alternator and where the senders are threaded into the motor - Oh - and check for any possible wire insulation chafe too.

Charles

Charles,

Thank you for your input. Guess I will have to take the panel off, and check the wiring.

Another forum member had the same issue last month http://forums.hunter.sailboatowners.com/showthread.php?t=174183 However, he did not post how he resolved it.

 

[Bill Roosa]

I'd check the ignition switch after a quick check for loose or broken wires. You will need a test lamp or multimeter to see if there is voltage on any output terminal of the ignition switch. There should be none in the off position

 

[Ken Cross]

another possability

You could also have a grounding problem where an open ground allows potential from some other source to power backward through the light and buzzer. This would be similar to the conditions the seem to confound owners of boat trailer lights. This problem on trailer lights goes away if you add a dedicated ground wire so to not rely on chassis grounds.

I haven't seen this happen, but it certainly could.

Ken

 

[Benny17441]

You have a short, with the Key switch at OFF there should be no power to the buzzer and lights. Your short is likely on the wiring harness going from engine to control panel. The harness is likely old and has lost elasticity; it is routed around sharp fiberglass corners and with hull flexing the insulation likely got chaffed over time. Trace the harness back along its routing looking for breaks in the insulation, paying special attention along corners. If a visual inspection does not reveal a break then you may have to test for continuity along the pin connectors of the harness. This is the most likely issue as power is being diverted and is by-passing the key switch. When the insulation of more than one wire is stripped in the harness it shows as a pot luck of symptoms depending on which wires were shorted; some loose power altogether while others just to the starter solenoid but most seem to develop problems with the warning lamps. After all there is nothing else.

 

[pateco]

You have a short, with the Key switch at OFF there should be no power to the buzzer and lights. Your short is likely on the wiring harness going from engine to control panel. The harness is likely old and has lost elasticity; it is routed around sharp fiberglass corners and with hull flexing the insulation likely got chaffed over time. Trace the harness back along its routing looking for breaks in the insulation, paying special attention along corners. If a visual inspection does not reveal a break then you may have to test for continuity along the pin connectors of the harness. This is the most likely issue as power is being diverted and is by-passing the key switch. When the insulation of more than one wire is stripped in the harness it shows as a pot luck of symptoms depending on which wires were shorted; some loose power altogether while others just to the starter solenoid but most seem to develop problems with the warning lamps. After all there is nothing else.

Does anyone sell a replacement harness, or should I build from scratch?

 

[HMT2]

Before I go chasing down a short in my wiring hareness I would take the panel off and check that all of the connections at the back of the panel are clean and tight. I couldn't see the picture of your panel. But I replaced mine recently and pretty inexpensively. I had an alarm issue with my oil pressure alarm. It ended up being a faulty sensor, pretty easy fix. It wasn't clear to me which alarm was activating.

 

[pateco]

Before I go chasing down a short in my wiring hareness I would take the panel off and check that all of the connections at the back of the panel are clean and tight. I couldn't see the picture of your panel. But I replaced mine recently and pretty inexpensively. I had an alarm issue with my oil pressure alarm. It ended up being a faulty sensor, pretty easy fix. It wasn't clear to me which alarm was activating.

My existing panel already had a crack in it, so I ordered a new empty Panel last week, and when it arrives this week (hopefully), I will disassemble the existing panel and transfer everything to the new one. I will clean and test all connections as I go. If I am lucky, this will fix the issue. I will let you know what I find.

 

[Benny17441]

Does anyone sell a replacement harness, or should I build from scratch?

The engine harness for the 2GM20 is Yanmar Part Number 128270-77921 $89.15.

The 3 meter extension which goes from engine to control panel is part number 128170-77500 $87.25.

2 things to watch for before ordering the harness from your Yanmar dealer;
1) make sure your problem is the harness and which part of the harness and have your dealer corroborate the part numbers to your particular engine and control panel as there are variations.

The thing is that once you have diagnosed where the problem is you are already there and a fix is usually as simple as stripping and splicing back the wires and adding tape for insulation. Carefully done repairs usually last for many years extending the life of a harness. The extension from engine harness to panel harness is easier than you may think to get at, remove screws holding the panel and gain access to the back. Disconnect the pin connector and drop down. On a Cherubini I would say you can gain access through the starboard lazarette to make sure any attachment straps are removed. Remove the Pin connector from the engine and pull the harness extension out. You can now do a thorough visual inspection and test the pins from one end to the other for continuity . Replacing it is a matter of reversing the steps with the routing mostly evident by the existing bends in the harness. There is nothing to say that the problem could not be in the engine part of the harness or at the panel end wiring and those ones perhaps should be checked first making sure there are no loose or stripped wires or bad connections. I'm just pointing to the harness extension as the most common place for a short to occur.

 

[Benny17441]

Does anyone sell a replacement harness, or should I build from scratch?

The engine harness for the 2GM20 is Yanmar Part Number 128270-77921 $89.15.

The 3 meter extension which goes from engine to control panel is part number 128170-77500 $87.25.

2 things to watch for before ordering the harness from your Yanmar dealer;
1) make sure your problem is the harness and which part of the harness and have your dealer corroborate the part numbers to your particular engine and control panel as there are variations.

The thing is that once you have diagnosed where the problem is you are already there and a fix is usually as simple as stripping and splicing back the wires and adding tape for insulation. Carefully done repairs usually last for many years extending the life of a harness. The extension from engine harness to panel harness is easier than you may think to get at, remove screws holding the panel and gain access to the back. Disconnect the pin connector and drop down. On a Cherubini I would say you can gain access through the starboard lazarette to make sure any attachment straps are removed. Remove the Pin connector from the engine and pull the harness extension out. You can now do a thorough visual inspection and test the pins from one end to the other for continuity . Replacing it is a matter of reversing the steps with the routing mostly evident by the existing bends in the harness. There is nothing to say that the problem could not be in the engine part of the harness or at the panel end wiring and those ones perhaps should be checked first making sure there are no loose or stripped wires or bad connections. I'm just pointing to the harness extension as the most common place where these shorts occur.

 

[pateco]

So I changed out the panel yesterday, and found only one wiring issue. Engine hour meter is wired across the ignition switch. See the two green wires in the picture.

It still reads 0000.0 Hours so it must have burnt out instantly when it was installed. I will probably replace it by relocating the Fuel Gauge from below in the starboard lazarette.

After transferring all of the gauges, lights and switches to the new panel, All wiring looked to be in good condition. Still getting the charge light while the engine is running, so next step is to check the alternator out. and maybe replace.

Old cracked and faded Panel.

New panel installed.

 

[pateco]

I also managed to free up the engine stop cable that has been frozen since we got the Stargazer. A little PB Blaster and Ultralube did the trick. Works like a charm now.

 

[woodster]

if its the alt take it to an automotive electric shop and have it repaired .....lot cheaper than buying a new one

 

[Charles Erwin]

The hour meter install is not the source of your intermittent charge alarm. Trace the blue/black charge wire and verify it is not chafed touching the motor block or other battery negative source.

By the way - the hour meter is connected wrong. Maybe it is not burnt out. The meter terminals should be marked plus and minus. Put the plus on the switched side of the ignition terminal - the one that leads to the starter button - and the minus at battery negative. Worth a shot and better at gauging fuel than a fuel gauge too.

Otherwise follow Woodster's suggestion,

Charles.

 

[woodster]

while we are on the subject get you some better wire for that hook up...used tinned wire and some heat shrink connectors..it is damp in that cavity ...and put some dielectric grease/lub on the quick connects on that harness