Engine Safety Shut Off Switch Refit

[Bwhntr31]

I would like to refit a a new engine safety shut-off switch on my 1987 Johnson 75-HP engine

Q1: I have the original [remote] control box. Can I get a new switch with the [engine safety shut off] switch that will replace the older switch?

Q2. I have a new [remote] control box that has the[engine safety shut-off] switch, but the control cables on the (PMC 1970's]
outboards [engines] are different. Can I adapt the original cables?

[jimh]

Q1: I have the original [remote] control box. Can I get a new switch with the [engine safety shut off] switch that will replace the older switch?

The engine safety shut-off switch usually functions to suppress the spark ignition voltage on a two-stroke-power-cycle engine. On some engines the circuit for the engine safety shut-off switch uses a NORMALLY CLOSED switch which becomes OPEN when the LANYARD is pulled out of the switch mechanism. On other engines, the engine safety shut-off switch uses a NORMALLY OPEN switch which becomes CLOSED when the LANYARD is pulled out of the switch mechanism.

If you wish to replace an existing engine safety shut-off switch with a new switch, the replacement switch has to be chosen to match the switch action of the original switch, that is, has to be either a NORMALLY CLOSED switch or a NORMALLY OPEN switch, depending on the method used in the outboard engine.

Q2. I have a new [remote] control box that has the [engine safety shut-off] switch, but the control cables on the (OMC 1970's] outboards [engines] are different. Can I adapt the original cables?

The engine wiring harness assembly on OMC engine changed from the original configuration used from 1972 to 1995 to a new configuration in 1996 called the MWS wiring harness. The two wiring harnesses use different connectors. If you have an engine with the older c.1972 wiring harness, you cannot use remote controls and instrumentation designed for use with the MWS c.1996 wiring harness, unless you canabalize the wiring in the newer remote controls and the older wiring harness and try to make butt-splice connections between them. This approach would be a very poor way to implement the remote controls solely for purpose of replacement of the engine safety shut-off switch. I very strongly recommend against such a radical modification of the wiring harness and the remote controls. This would be the worst possible approach.

All that is needed to implement the engine safety shut off switch replacement is to obtain the proper switch with the proper action.

[Thread has been moved to SMALL BOAT ELECTRICAL for discussion.]