I bought a new tach for my boat I have a 1975 wellcraft V20 steplift with a 1975 115 Mercury 2 stroke O/B I'm not sure how the wires go. I have the harness from the old tach there are 3 wires bat, grnd and sender. I enclosed
a pic of the new tach . the dial on the old Tach was set to alt but the new Tach doesn't have alt what do I set it to
a pic of the new tach . the dial on the old Tach was set to alt but the new Tach doesn't have alt what do I set it to