Re: ignition for 1985 johnson 45hp commercial outboard
Ignition is called Magneto Capacitance Discharge, a stator assembly under flywheel applies voltage to powerpack ( electronic solid state ignition).
The commercial 45hp Johnson does not come equipped with a charging system which is needed to operate a tachometer which normally operates off of the charging system six (6) pulse output..... the tach would have a dial on the back of it that can be set to number six (6).
Perhaps a charging system has been added to your engine at some point? If so, there will be a rectifier located on the engine, described as follows.
(Small Rectifier Description & Location)
(J. Reeves)
On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.
The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:
One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.
Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue.
If indeed you have no charging system, another type tachometer will be required. Hopefully one of the other members will inform you of those choices.
