One of my motors has a tach that bounces here and there. Just little jumps occasionally. Anything specific I could check in the wiring before I start looking into the coil? I'm going to swap the leads at the two tachs to try and see if it is the guage....

i took my boat out yesterday and for about a half a day the tach would bounce.toward the end of the day the tach stoped bouncing.i have been told theis is moisture in the gage.i do not know what the fix would be,maybe a replacement.