What is the best way to trouble shoot a non working RPM indicator on my Boat.?

Question

The engine is a Mercury Outboard 115 HP 2001 Model

Answer 1

Mercury outboards have a problem with tacks replace it>

Answer 2

instead of driving yourself nuts....replace the tac and cable.....in the end it will cheaper and you will save much more mental stress....TRUST ME!!!

GOOD LUCK

Answer 3

First check your connections on either end.  Be sure they are tight.  If that doesn't help, buy a new tach.

Answer 4

careful of "not good answers".  use a simple voltmeter to test if you're battery is being charged when the engine is running.  if it is, check the gray wire from the rectifier to the dash.  if it has continuity, it's the tach.  oh, most important, make sure when the key is on you have 12v. to the tach.

Answer 5

the rpm gauge works off the negative side of the coil follow the wiring from the gauge to the coil if still connected the gauge is bad