Re: Tach install for '74 50hp
tachometers read off the alternating pulses from the stator. Any of the leads from the stator charging portion can be used for the signal. The designated tach signal wire is merely attached to one of those. Tachs have rotary switches on the back that set it to different numbers of coils in the charging circuit, times two because there is a positive and negative pulse for each coil for each cycle. Tachs measure pulses. That being said, you need a tach that has the setting that you need designated on the rotary switch.
The BRP tach of the right model comes with a harness that you can plug and play. The Teleflex tachometers offer the harness as well.
http://www.iboats.com/Teleflex_Tacho...-view_id.40245
Or you can easily wire most tachs, that have the correct settings on the rotary dial of course, by either going directly to the ignition switch or by cutting into the main harness.
