Tacho failure

[silverback]

The tacho on my yanmar 6lpa has stopped. Strangely, however, the hour meter part is working as is the alternator. Any thoughts please?

 

[Bacchus]

Don't know about the 6LPA but I know the 6LYAs tach is from a sensor on the engine bell housing. I would start with checking connections on back of tach if not done so already.
Mine was erratic last spring and it turned out to be corrosion on terminals / connectors to the sensor.

I have also read the sensor or spot on the flywheel can get dirty but the spacing is critical so don't just remove the sensor to check.
The procedure I read about but didn't have to use, was to gently screw the sensor in until it touched and count / record the turns / partials required. Then remove the sensor to clean or replace. Install using the reverse... in until gentle contact then back it out the recorded # turns.
Good luck & pls report back.

 

[silverback]

Thank you Bacchus. Drew sensor and gave a wipe pretty clean though. Unlike blade connections. Bit of a clean up of connector blades and we are back in business��

 

[Bacchus]

[emoji106]

 

[Alan Mainship]

Thank y’all, bet that is my problem also,have been hitting with flip/ flop! Maybe you found the cure for me?

 

[silverback]

THEY ( you know the ones) had all assured me that tacho was driven by pulses from alternator! Now am one of the know alls, at least with this tacho. A wee dab of dielectric grease and good to go����

 

[Bacchus]

THEY ( you know the ones) had all assured me that tacho was driven by pulses from alternator! Now am one of the know alls, at least with this tacho. A wee dab of dielectric grease and good to go����

Alt is one (common) way of doing it but NOT THE ONLY ONE.
I think I found that in the Yanmar Service Manual.
Downloadable Copy posted/available in the TF Library Manual section

 

[silverback]

Thank you