I want to put a Tach on this '65 60hp Johnson. I got a automotive with setting for 6cyl or 4 cyl set up. I put it on 4cyl and hooked it per instructions (one lead to battery one to switch and one to the engine) The one to the engine I hooked to spade terminal on the Magneto houseing. I get no reading when i run it. Is it hooked right? Will this Tack work?, What can/should I do? Thanks
