SailNet Community - View Single Post - bouncing tach
Thread: bouncing tach
View Single Post
Old 09-07-2013
Faster's Avatar
Faster Faster is online now
Just another Moderator
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 16,208
Thanks: 100
Thanked 290 Times in 280 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
Re: bouncing tach

Depends on your pickup/sensor/tach drive method.

Tachs are usually driven either by an alternator/regulator output or by pickups mounted at the flywheel.

Have you noticed your charging system falling off at the same time? That would point to a developing alternator problem. If the tach is not alternator driven then it's possible the speed sensor connections are failing, or the sensor has vibrated out enough to lose the required proximity to the teeth or slug that drives it.

I'd say a connection somewhere is the most likely culprit unless there are other alternator related symptoms.

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Share with Facebook