Tachometer for Yanmar 3JH2TCE

[HueyHuey]

Hi, I'm looking for replacement tachometers for my Yanmar 3JH2TCE. I have the panel it's just the tachometer that I need, it says P=114 YM-0234-001.
I have found several on eBay but they have different numbers eg P=116 or P=117 etc.
What does the P stand for and can I use non Yanmar aftermarket tachometers and where would I get them and do they need adjustment for setting up?

[Wotname]

The P is the numbers of pulses per single revolution of the engine. It equates to the number of teeth on the ring gear on the flywheel.

The Yanmar alternator pickup counts the number of teeth that pass it per revolution and creates one pulse per tooth.

You can use a variety of aftermarket tachs and some can be sensed by the Yanmar flywheel tach sensor and others can be sensed by the alternator 'W' lead.

Not all alternators have the 'W' lead fitted but all alternators can be modified to have this 'W' lead.

[Wotname]

Note: some aftermarket tachs can be adjusted over a wide range, some over a small range and some can't be adjusted at all.

Some can be adjusted by dip switches, some by a trim pot and some by computer programming (either in the field or in a workshop). There is quite a variety of options .

[chrisr]

just a little off topic (sorry) but we have the same issue with tacho on one of our 4JH2-HTEs

one reason i've put of getting a new one is the hour meter

does anyone know if it is possible to re-set the hour meter to match the actual reading on the tacho being replaced ?

cheers,

[bailsout]

When my Yanmar tach stopped working two years ago, I removed it. I didn’t replace it. I have no tachometer problems now.��

[stormalong]

Originally Posted by chrisr

just a little off topic (sorry) but we have the same issue with tacho on one of our 4JH2-HTEs

one reason i've put of getting a new one is the hour meter

does anyone know if it is possible to re-set the hour meter to match the actual reading on the tacho being replaced ?

cheers,

Hour meters are usually tamper resistant for obvious reasons. My old VDO tach would not log hours unless it got pulsed. When it broke I wrote the old hours in the logbook and started anew. I saved the old tach if anyone wants to see it.

[Scubaseas]

This one should work but check the manual first. Righteous seller. I got fuel filters from him.

https://www.cruisersforum.com/forums...er-246115.html

[OldGreyB]

Originally Posted by chrisr

just a little off topic (sorry) but we have the same issue with tacho on one of our 4JH2-HTEs

one reason i've put of getting a new one is the hour meter

does anyone know if it is possible to re-set the hour meter to match the actual reading on the tacho being replaced ?

cheers,

Chrisr,
If you are hands on, or have a friend whom is hands on then just replacing the hour meter may work for you. I have two on order at this time for the same reason. See these links:

How to replace the hour meter:

https://www.youtube.com/watch?v=PFkSwD5-mfw

One of many sites offering the hour meter (Note Yanmar and VolvoPenta all appear to use VDO or equivalent OEM meters):

https://www.ebay.com/itm/LCD-Display....c101195.m1851

According to my research the replacement hour meter shows the correct hours as that information is held within the tachometer head, so changing the hourmeter only allows one to maintain the original hours run. Until I have completed my change outs I will not know for sure.

[Scubaseas]

Originally Posted by chrisr

just a little off topic (sorry) but we have the same issue with tacho on one of our 4JH2-HTEs

one reason i've put of getting a new one is the hour meter

does anyone know if it is possible to re-set the hour meter to match the actual reading on the tacho being replaced ?

cheers,

Contact a speedometer repair company and they can probably do it for you. The Yanmars are basically an hour meter inside the tachometer. Some later Volvos the hour meter is just a display and the hours are adjustable with the proper software and tooling. There are several YouTube videos showing how to replace or repair an hour meter in a Yanmar/VDO tachometer. You can probably send your tach into a speedo shop and have them replace the hour display and set the hours to whatever you need. I'd also make a statement when you sell the boat that the hour meter may not be accurate the same way most auto titles have a space for.

[neworleansrich]

FYI replacing or adding a tachometer to diesel engines.

Most inexpensive, off the rack, tachs (like Sierra) are only set up to accept spark pulses for 2 4 6 or 8 cylinder gas engines. Diesel engines commonly use either a gear sensor or alternator pulse train, hence the number of pulses per revolution can be almost anything. For example, I have a Cat 3126b that produces 120 pulses/revolution.

I found these cheap Tachs on eBay sold by many different "overseas" sellers that offer an alternative:


https://www.ebay.com/itm/85mm-Car-Tr...53.m2749.l2649

While, the descriptions do not explicitly say what range of pulses they can accept, it turns out they can be set to very wide range, up to at least 200 pulses/rev.

[chrisr]

Originally Posted by OldGreyB

Chrisr,
If you are hands on, or have a friend whom is hands on then just replacing the hour meter may work for you. I have two on order at this time for the same reason. See these links:

How to replace the hour meter:

One of many sites offering the hour meter (Note Yanmar and VolvoPenta all appear to use VDO or equivalent OEM meters):

https://www.ebay.com/itm/LCD-Display....c101195.m1851

According to my research the replacement hour meter shows the correct hours as that information is held within the tachometer head, so changing the hour meter only allows one to maintain the original hours run. Until I have completed my change outs I will not know for sure.

many thanks. our tachos must be fairly old as they seem to use a fully mechanical hour meter...

cheers,

[chrisr]

Originally Posted by Scubaseas

Contact a speedometer repair company and they can probably do it for you. The Yanmars are basically an hour meter inside the tachometer. Some later Volvos the hour meter is just a display and the hours are adjustable with the proper software and tooling. There are several YouTube videos showing how to replace or repair an hour meter in a Yanmar/VDO tachometer. You can probably send your tach into a speedo shop and have them replace the hour display and set the hours to whatever you need. I'd also make a statement when you sell the boat that the hour meter may not be accurate the same way most auto titles have a space for.

many thanks. that looks like what i'll need to do. trouble is these days nobody wants to repair anything...just replace with another bit ex china !

btw, our hour meters look to be 100% mechanical...

cheers,

[Wotname]

Originally Posted by chrisr

many thanks. that looks like what i'll need to do. trouble is these days nobody wants to repair anything...just replace with another bit ex china !

btw, our hour meters look to be 100% mechanical...

cheers,

Here you go, get these guys to repair your tach.
https://www.ottoinstruments.com.au
or these guys
vdo gauges tachometer smiths chronometric marine speedometer instrument repairs dials speed limiting

I have used the first one to repair a Smiths tractor tach (mechanically driven c1960) and friends have used the second one.

Both repairs were well done and reasonably priced (IMO).

NAMIISS (NSW) https://www.gauge-shop.com.au may be able to do it also but I haven't used them for repairs, only for new items. They were easy to deal with and seemed to know their stuff.

[HueyHuey]

I might try one of the repairers first, as one tacho (revs) doesn't work and the other the hours are intermittent. It would be easier if both worked correctly, at least I can match both controllers for revs and I know roughly what the hours are from the one that works...😅

[Wotname]

HueyHuey, I didn't realise you were in Oz, so yep, get a quote/estimate from one of the repair shops I mentioned upthread.