tac and gas guage problems

[jeff6898]

79 85hp evinrude 85999R

Replaced ingnition switched yesterday. Before I did that gas guage did not work and tac worked great. Now the gas guage works and the tac stays pegged out at full. Seems there is a purple wire connected to the switch that when I play with it makes the gas guage needle jump. Does this purple wire have anything to do with the tac and gas guage?

 

[rickdb1boat]

Re: tac and gas guage problems

Yes, the purple wire is the ignition (12 volts) wire. It would hook into the the fuel gauge "I" terminal as well as the Tachometers "I" terminal. Look for a bad or corroded connection at the gauges.