Older Johnson safety switches

[gjonz]

There have been previous threads about 1950's Johnson's having a mercury safety switch on the throttle to prevent runaway motors.

My two 1956 RD's are missing these mercury safety switches. Should I bypass that circuit, or can I find a replacement?

How necessary are they?

Thanks!

Greg

 

[freddyray21]

Re: Older Johnson safety switches

they are there to prevent the starter from engaging at anything above a high idle. I have had motors with them working and not. As long as you always have the motor out of gear and the idle down you can get by. They are still available and not that expensive so I would just replace it and make it right.

 

[F_R]

Re: Older Johnson safety switches

they are there to prevent the starter from engaging at anything above a high idle. I have had motors with them working and not. As long as you always have the motor out of gear and the idle down you can get by. They are still available and not that expensive so I would just replace it and make it right.

That is a true statement as related to the motor in question. However, lest somebody with a different model be reading this, on some the mercury switch is also tied in with the vacuum cut-out switch which prevents run-away. To be honest, I'm not sure if that is the case with the 30 or not. If the vacuum switch is mounted on a plastic plate, it is true.

A large majority of motors are running around with neither switch working. That doesn't make it right. In fact, it makes it dangerous in the starting part. Running over another boat, or worse--a person will ruin everybody's day.

 

[coolguy147]

Re: Older Johnson safety switches

only one id be worried about is the older 40hp motors. those were runaways and had some crank shaft problems i heard

the motor im working on has a cit wire on it and is most likely dienagaged the vacum thing. mainly for if u hit a stump and ur motor pops up

 

[gjonz]

Re: Older Johnson safety switches

Anyone have a part number for the mercury switch that mounts on the tiller shaft?

I appreciate the help. I am trying to do a proper restoration on these motors and givent their importance to safety, I feel it is impairative to restore this feature.

Thanks again!

Greg

 

[F_R]

Re: Older Johnson safety switches

Should be 376323

EDIT: Btw, I checked the wiring diagram and it does not show that year as connecting the mercury switch to the vacuum cut-out. So, it just provides the starter limitation to slow throttle.

 

[gjonz]

Re: Older Johnson safety switches

Thanks guys!

Ordered the switches from Sea-Way marine. Very expensive. 7.95ea!

Greg