Help with tach problem (Yamaha C75TLRS)

Dear all,

My Yamaha C75TLRS which is mounted on Skeeter SS90 bassboat runs correctly, I have not problems with it, but unfortunately some time ago the tachometer started to fail (analog type, it is the original part), it shows an illogical measure of the rpms, too low or too high without logical sense. Can you let me know how to proceed to identify the problem or the part that I need to replace (could be the sender unit or the tachometer?), any advise or comments will be welcome!

Thank you in advance.
Jesus L.

[boats.net]

Most of the time it's a bad tach.

[robert graham]

check all wires on back of tach to be certain it's not loose or corroded connections, then if that's not it, then buy a new tach and install. mine lasted about 5 years and died, replaced with a better waterproof model, not very difficult to install. calibrate with small multi-position screw on back as per instructions. easy fix!

Dear All, thank you very much for your feedback, I will follow your advises.

Best regards,
Jesus L.