Jumping Tach Fix

[Red Monster]

My old tach started jumping now and again. The RPM of the engine didn't change, but the needle on the tach would suddenly spike. With a little online research, I found this problem can be caused by a selector switch on the back of the tach and can be fixed by simply turning the switch back and forth a few times.

http://www.v3instruments.com/trouble_shooting_guides/tachometer_switch_cleaning_procedure.pdf

I tried this and so far there has been no more jumping tach readings.

 

[trophywife]

tap the glass a few times

 

[Red Monster]

Tapping the glass is not the same as turning the switch on the back.

I took the boat out and the tach did not jump/spike any more!

If you have an older boat, you may find this tip comes in handy at some point.

 

[fshnfnatic]

Good tip, RM. I had a tach do that to me years ago.I thought it was f@#$ed,so I replaced it with a new one.May have
just been fine!!