New Tachometer for Yanmar 4JH3

[HenryD]

Hello,
I am redesigning my helm station and need to replace the tachometers. The current tachs are over 3" and just too big. I can find 2 1/16" tachometers but they are designed for gasoline engines.
Any suggestions?

 

[N4712]

Hello, I am redesigning my helm station and need to replace the tachometers. The current tachs are over 3" and just too big. I can find 2 1/16" tachometers but they are designed for gasoline engines. Any suggestions?

Go digital (Nmea2k).

 

[RT Firefly]

Greetings,
Lauderdale Speedometer and Compass

 

[HenryD]

N4712
I have NMEA2000 that works very well. The analog tachometer's will be backup.
Thanks

 

[N4712]

N4712 I have NMEA2000 that works very well. The analog tachometer's will be backup. Thanks

Ahh ok, then like RTF said try using Lauderdale speedometer and compass, they did a lot of the work on our heavy machinery.

 

[HenryD]

Thanks - will first thing in the morning.

 

[FF]

Any tach in a twin engine boat should be driven with a mounted tach drive , not simply from the alternators.

The alt driven units are only an approximation of the actual RPM , as belt tension , pully condition all are variables.

Fine for a single , where you just wish to get back to a sweet spot with no effort.

Much Un-good with twins if you are attempting to match the RPM to get rid of noise and droning .

 

[LarryM]

Hello,
I am redesigning my helm station and need to replace the tachometers. The current tachs are over 3" and just too big. I can find 2 1/16" tachometers but they are designed for gasoline engines.
Any suggestions?

I would check with Lauderdale as was mentioned by other posters. Here is some reference info for you on your JH:

The tachometer on Yanmar 4JH3 series diesels utilize a magnetic pickup sender (MPU) which converts the rotary motion of the engine to an electrical signal by counting the number of teeth on the ring gear.

The ring gear has 116 teeth and the output voltage of the MPU is 1.0V or higher at 500RPM measured across a 20kOhm load.

If you want to go with NMEA2000 instrument integration, life just got easy. Maretron manufactures a model EMS100 interface that plugs directly into the factory engine wiring harness on Yanmar GM, YM, JH, LP and LY series engines. Couldn't be simpler.

Good luck

LarryM
m/v Boomarang