Tach not working

[Jon Mutiger]

Hi there, I'm about to buy a boat with a bf40, about a 2005. The boat and motor appear to be in great shape but the tach isn't working.

I'm mechanically inclined and have a multi meter. I'm guessing the guage needs power, ground and a trigger signal. Can someone explain to me how the factory Honda tach is meant to work so I can try to diagnose what's wrong?

Thanks,

Jon

 

[Sea Rider]

Welcome to Iboats,

Tach works with signal cable coming from OB, power & ground, check if tach has pulse selector at rear. Probably not set correctly ?

Happy Boating

 

[Jon Mutiger]

Is the pulse signal a digital signal or variable voltage? If it's digital I won't be able to use the meter effectively.

 

[Sea Rider]

Assume it's digital pulse..

Happy Boating

 

[hondam]

Neither it is an analog signal, the tachometer measures the frequency of the analog signal coming from the motor and cannot be reliably measured with a standard DVM. The voltage may vary slightly but is not the measurement the tachometer is taking.

The tachometer runs off the the charging system, if your charging system is operating properly then its probably the gauge.