Replacement Tach for Yanmar

[Bob Waters]

Hi Tony,

I phototached my Yanmar tachs yesterday. The engines are 4LHA-DTE- 200 hp.

At 3,000 rpm, port read 2846 and the Starboard was at 2853.

I want to replace with accurate tachs. I have a tower that does not have tachs so I want to add 2 sets. One set for both stations. I need recommendations for tachs and sensors.

I guess I need to replace the sensor on each engine, but can one sensor support two tachs?

I also did the no load test and the WOT in the slip was just under 3900 rpm.

The specs in my manual list low idle at 750 rpm and high idle at 3700. Is the 3700 the no load WOT? If so then based on tach error, the high rpm rpm is correct.

Topic

[Bob Waters]

Charles.
I have the installation finished. I pig tailed the new sensor wire to the yanmar switch with a double spade. Works very good.
Thanks,
Bob

[Charles Jourdan]

Hi Bob 

I  forgot to add that the Aetna manual shows that you can add  upper and lower tachs to the same  magnetic pick up.   You can go to their website and download all their installation instructions.

Charles

[Charles Jourdan]

Hi Bob

I used the original flywheel pickup that came on the motor.   It should be a direct connection unless the boat manufacturer bypass the pickup and wire off the alternator which  your rpm could be off by a few hundred.

Charles

[Bob Waters]

Hi Charles,

Thank you for the corrected flywheel tooth count. Did you use the Yanmar sensor or did you have to replace it?

I’m not sure if this is possible, but I would like to retain my original Yanmar guage set at the lower helm and add a Tach at the tower helm. That would require me to add the additional wire at the sensor to the Aetna tach. If this is possible, I can still use the original tach with hour meter.

 

Bob

[Charles Jourdan]

Tachometer

Hi Bob

Your flywheel has 127 teeth.  I just installed a set of Aetna LCD techs and am very happy with there performance.  I know they are a little pricey but quality and factory support is good.  Hope this helps.

Charles

[Bob Waters]

Hi Tony,

 

Well that tach is sure inexpensive. Have you used them and will they work with my Yanmar sensors.

I was inquiring about replacement tachs, not OEM tachs. I checked the Aetna web page and their tachs cost 262 to 296 each. Aetna has tachs that have hours meters in them, which is a plus. I was thinking of changing tachs at lower helm with hour meters and tower without hour meters. The aetna tachs need tooth count of flywheel, which I think is 137.

Thanks,

Bob

[Tony Athens]

Bob,   We really do not have anything that would fit a Yanmar Panel..   Why not spend $30 and buy 2 of these.. Tell us how they work? http://www.tomtop.com/tachometers-1549/p-k975b.html?currency=USD&aid=gpla&gclid=CICslenmgNICFQx9fgodM-kC3Q   Tony    

[Bob Waters]

Yes, Tachs read 150 higher than actual.

Do you sell replacement tachs and sensor?

Bob

[Tony Athens]

“High Idle”  Is a term meaning “no Load” RPM..

So are your tachs reading about 150R high compared to real, or is it the opposite?

Why Yanmar does not make their tachs with a vernier adjustment simply amazes me

Tony

 

 

 

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