Key Kill Switch

[Scott's B haven]

I have a 1943 B I am trying to put a key switch on it but it has a mag. I"m confused on what wires go where.HELP!
Thanks Scott

 

[P Browning]

Why do you want to install a "kill switch"? That model tractor is to be shut down by turning off the fuel and allowing the engine to run until the fuel supply dries up. This procedure is oulined in your operators manual, and has purpose. Just because these tractors were once operated on distillate and now aren't isn't sufficient reason to arbitrarily change the shut-down procedure. Besides, installing a grounding system on the magneto provides yet another path for failure; something else to short out and give you grief.

But if you must know, the magneto needs to have an external terminal -- WICO Type XH magnetos will generally have one. WICO Type C won't. When you appply a connection between the magneto's external terminal and chassis of the tractor, you short the magneto output (at the points) to ground and the tractor will stall. (PatB)
Restoration Site, JD-H

 

[John T]

Scott, Some cheap general purpose generic key type ignition switches may only have 2 terminals being a normally open contact which is closed when switched on cuz they are intended to provide battery voltage to a coil in the on run position. (It would take some rigging to use such a switch) You need to get a key operated switch that has at least one set of normally closed contacts that are closed in the OFF position (to kill the mag)but opened in the ON position. Some lawn n garden type key switches work that way cuz in the off position they ground out n kill a mag type ignition, that may suit your needs just fine......

Then you run a wire from the mags kill switch (if it has one like Wico X models can have) up to the switch attached to a terminal that gets switched to frame ground when OFF (to kill the mag) but floating disconnected when in ON allowing the mag to fire. It may be necessary to attach one switch terminal to the mag and the normally closed (when OFF) associated terminal to frame case ground unless the switch gets a frame case ground via its mount to the metallic dash etc

A key type switch can be a good safety feature (like at shows or around kids) cuz as long as its locked off the mag is dead, but I still shut mine down like Pat mentioned by turning off the gas as thats better for the engine.

Some Wico X Mags have the external kill stud but others dont although they can be purchased and wired in. Im unsure what other makes n models come equiopped with the external kill stud???

John T

 

[Gary from Muleshoe]

I agree with Pat, let it run out of fuel to shut down. I have a 1940 B that the previous owner put w kill switch on. When it is shut down using the kill switch I have to pull on the fly wheel 4 to 6 times to start it. When I shut it down by letting it run out of fuel, it starts on the first pull. There is a reason for this method. Kill switch is good for emergencies but other wise use the tradition method.

 

[Kemper]

Maybe the reason he wants a key is to keep someone from stealing it?

If you install a key switch,always shut off the gas and let the tractor die then shut off key...

 

[John T]

Looks like we all agree on that one,,,,,, Thats why Deere n others recommended that method of shut down for yearssssssssss since way back when cuz you dont want all that raw gas left inside the cylinders (as when using a kill switch) to wash off the oil from rings n cylinder walls and to be on the plugs either grrrrrrrr

John T

 

[Anonymous-0]

Pst-

Kill switches are a very good way of killing the tractor while STILL ON THE SEAT in case of an emergency (i.e., the clutch fails to disengage)

If the clutch does not disengage, the farmer will have to run the whole thing out of gas.

 

[Scott's B haven]

Guys I put a key on all my old John Deere for safty and thats all. I run the gas out to shut them down.thanks for the feed back.

 

[Mike M]

You can use a regular key switch,toggle ,or push pull, but it will work backwards. When in the on position it will make contact to ground as you have to hook one side of the switch to ground and the other to the mag.
You can also put one of those little button shut offs right on the mag post.

These are a very good idea for saftey , but I always seem to forget about them and then wonder why the heck it won't start ? DUH the switch !

 

[johns48jdb]

or simply reach over and pull the plug wires out of the mag.

 

[Anonymous-0]

That's quite a reach for someone with a bad back.