Tacho failure

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silverback

Veteran Member
Joined
Apr 7, 2017
Messages
45
Location
Australia
Vessel Name
Resolute
Vessel Make
Selene 48
The tacho on my yanmar 6lpa has stopped. Strangely, however, the hour meter part is working as is the alternator. Any thoughts please?
 
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.
 
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��
 
[emoji106]
 
Thank y’all, bet that is my problem also,have been hitting with flip/ flop! Maybe you found the cure for me?
 
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����
 
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
 
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