I have a '89 Johnson 50hp, 2 cyl, I cannot find in my manual or on the internet instructions regarding the correct hook up for the two wires from a "testing" tach to this engine in order to get the rpm for tuning low and high end.
I have found different opinions (i.e. red to starter or hot, blk to grnd, and so forth), but as on older cars the distributor-to-coil offered the intermintant spark. This engine does not have points or dist.
I am also wondering how a marine handheld "tach" is designed differently. I dont want to formulize an auto tach base on 8, 6, 4, etc. The manual shows a pic of one, 2 wires.... but that is it
Who knows ?