Westerbeke 30B Tachometer Issue

[Rolihlahla]

The tachometer is not reading correctly: sometimes when the engine is not running it sits at 200 RPM; it idles but shows @ 200-300 too many RPM on the tach (engine runs normally); tach can be off as much as 700-800 RPm, but is normally off @ 500 RPM. Again, engine runs normally, this is a tachometer display/reading issue. Someone on Facebook suggested an electrical ground issue, but I am not electrician - any thoughts from the community?

 

[jssailem]

Welcome to the forum and SBO sailing in the Pacific Northwest.
Have you made any changes to your alternator? How does your tach get the signal from the engine, Manual or electrical?
If electrical what type of regulator do you have? Did anyone try to calibrate the tachometer?

 

[jviss]

I found that my tach doesn't read well when my batts are fully charged and on shore power.

 

[Rolihlahla]

Welcome to the forum and SBO sailing in the Pacific Northwest.
Have you made any changes to your alternator? How does your tach get the signal from the engine, Manual or electrical?
If electrical what type of regulator do you have? Did anyone try to calibrate the tachometer?

No changes to alternator, electrical, no idea what type of regulator, no one has tried to calibrate the tach: it has worked fine since I bought the boat 18 months ago, it just started misbehaving - and I hate PFM <grin>!

 

[jssailem]

Hi again. I see you posted about a 331 for an owner in SF Bay. That post was from 2021. One post about his engine, then nothing.

Did you get your Tach issue resolved?