Yanmar “Idiot” Lights Upgrade

[FireIslander]

Homer,

I am in the same position with the yamnar lights on an old 1977 27' Hunter. Just put in a new alternator and the lamp works but not the others. I just got this boat so working my way through the issues. The rubber boots are all dried out and I had ordered LED's but read somewhere that they can't be used because it requires the bulbs.....what did you end up doing?

Thanks

Mike
sailormn@optoline.net

[Wotname]

Originally Posted by FireIslander

Homer,

I am in the same position with the yamnar lights on an old 1977 27' Hunter. Just put in a new alternator and the lamp works but not the others. I just got this boat so working my way through the issues. The rubber boots are all dried out and I had ordered LED's but read somewhere that they can't be used because it requires the bulbs.....what did you end up doing?

Thanks

Mike
sailormn@optoline.net

While waiting for Homer to advise what he did, let me say the over temperature light and the oil pressure light can be LED. You do have to make sure they are connected the correct way as they are polarity sensitive. The negative side must go to the respective senders (switches) on the engine.

As for the alternator light, it is slightly more complicated as it depends on the alternator/regulator arrangements but at the end of the day, an LED can be made to work as an alternator light with other external circuitry. However if I understand your post correctly, this isn't an issue in your case as your alternator light is working OK.

[FireIslander]

Wotname,

Thanks for the response. I had purchased LED's then read that the alternator light had to be a bulb....What other circuitry would it need. I have a new panel that came with the boat, the tach is bad as well...those rubber boots are the real issue all dry rotted. After I installed the alternator I was just happy the light came on!!

One of the other posts said that guages can be installed instead of the lights.....any wiring changes need to be done? I never worked on a diesel so its all new to me.

Previous owners of this boat made chop suey of the the electric panel....Needs a complete rewire and I want to move the panel to higher ground.

Thanks

Mike

[Homer Shannon]

Wow, this post is so old I've forgotten what I did! We had no season in 2020 due to covid and family illness issues (not actually covid) but the lamps worked fine for the entire 2021 season. I know I didn't put in the LEDs, so I suspect I just cleaned up the sloppy wiring and left the bulbs as they were - cracked rubber boots and all.

A poor solution, I admit, but if it ain't broke...

[FireIslander]

Homer, Thanks...Yes I know that feeling.....The wiring on this boat was poorly maintained....and I just like things to work as they are supposed to...LOL

It's an old 1977 Hunter 27.

Mike

[Lake-Effect]

Originally Posted by FireIslander

Wotname,

Thanks for the response. I had purchased LED's then read that the alternator light had to be a bulb....What other circuitry would it need. I have a new panel that came with the boat, the tach is bad as well...those rubber boots are the real issue all dry rotted. After I installed the alternator I was just happy the light came on!!

One of the other posts said that guages can be installed instead of the lights.....any wiring changes need to be done? I never worked on a diesel so its all new to me.

Can you post or link to your panel schematic? Usually, when an incandescent bulb is specified as an important part of the circuit, it's because of a reliance on the bulb's resistance.

Does the alternator stop working or behave different if the alternator bulb is disconnected (as if it burnt out)? Or does the tach stop working? If there's no difference if the bulb is disconnected, then you can probably replace it with a 12v LED indicator.

If it turns out that the bulb's 'on' resistance is important, one can measure the voltage and current across the bulb when its on, then figure out the resistance ( = volts/current) then add a resistor in parallel with a 12v LED indicator so that it takes the same amount of current as the bulb.

[FireIslander]

I have to check the other two circuits, would be great if they can be connected by LED....not sure about polarity on them, another thing to check ha-ha!

I am attaching a schematic

[Lake-Effect]

Originally Posted by FireIslander

I have to check the other two circuits, would be great if they can be connected by LED....not sure about polarity on them, another thing to check ha-ha!

Where did you read that the alternator ("charging") lamp had to be a bulb? What's the bulb type or part number? Does it light when charging is ok, or if the charging has failed?

The schematic calls all the bulbs "pilot lamps", which suggests they aren't critical. One side of each bulb connects to +12v (the ON side of the key switch), the other side is the negative connection.

[cal40john]

Originally Posted by Lake-Effect

Where did you read that the alternator ("charging") lamp had to be a bulb? What's the bulb type or part number? Does it light when charging is ok, or if the charging has failed?

The schematic calls all the bulbs "pilot lamps", which suggests they aren't critical. One side of each bulb connects to +12v (the ON side of the key switch), the other side is the negative connection.

Might have gotten the idea from post #15 in this thread.

[FireIslander]

When I was looking for the alternator I read so many different posts on this without any one being definitive. It was one of the threads I read about the bulb being a bulb and not an led. something with the ohm rating.

I wanted LED because of the design with the rubber boots was plain stupid.

I have not run this engine yet as I only acquired it a short time ago.

Does the 2QM15 require the stop cable to stop the engine or just throttle it back. I plan on ordering a new stop cable since the old one was rusted stuck and I removed it already.

Thanks

[FireIslander]

Do LEDS have + or -? They seem to work in either direction.

[Wotname]

Originally Posted by FireIslander

.......

Does the 2QM15 require the stop cable to stop the engine or just throttle it back. I plan on ordering a new stop cable since the old one was rusted stuck and I removed it already.

Thanks

The 2QM15 does utilise a stop cable. When pulled, it allows the throttle arm to throttle back even further than when at idle. See the attached images. The red line is the stop cable, the green line is the throttle cable.

[Bycrick]

On my C type Yanmar panel, the alternator light bulb is a different part number than the other two bulbs, and has a specific wattage rating. The two types are not interchangeable.

I would worry about whether the two warning light (oil, temperature) were LEDs or not. The bulbs are lit so seldom that they’ll fail from corrosion, water damage or excessive vibration. LED won’t be much different. One potential reason to reengineer them would be if you find the lights hard to see in full sun.



A new Yanmar panel is likely to be quite pricey. And I don’t like the new electronic panels which have given me nothing but trouble.

[Wotname]

Originally Posted by FireIslander

Do LEDS have + or -? They seem to work in either direction.

Short answer - It depends on the circuitry packaged with the LED.

Long answer - A 'native' LED is polarity conscious and also needs a load resistor to operate on 12V. A LED sold as a 12V LED will have this load resistor packaged in the LED housing and will be polarity conscious. It may also have a bridge rectifier packaged into the housing allowing it to be non-polarity conscious.

[Wotname]

Originally Posted by FireIslander

When I was looking for the alternator I read so many different posts on this without any one being definitive. It was one of the threads I read about the bulb being a bulb and not an led. something with the ohm rating........

I'll get back to you latter today with a suitable (but simple) solution if you plan to use a LED with a 2QM15 stock alternator. I'm time short ATM.

Does your new alternator use the same wiring and terminals as the stock Yanmar one?