Ignition Switch

Whats the difference between the ignition switches for distributor and magneto systems. When you go to buy a new switch you have to specify if you have a distributor or a mag yet they both appear to be simple off/on pull type switches?

A distributor switch closes (shorts)in the on position to supply current to ignition system and opens to cut current to turn engine off.

Magneto switch closes to short out system to turn off, opens to run.

Talking about the IH pull switches, the MAG switch has ONE terminal, which gets grounded to the case when the switch knob gets mashed "DOWN".

The battery ignition switch has TWO terminals that are normally OPEN and get connected to each other when the knob is pulled "UP".

QUITE a difference!

The housings and buttons look the same, Bud. What differs are the guts.

For a battery ignition, it's a double-pole switch. There are two connections on the bottom of it, both insulated from ground. One is supplied from the battery. The other runs up to the ignition coil. With the mushroom-cap switch button in the down position, the connection between them is broken/open, so there is no juice running to the ignition. With the switch button in the up/run position the connection is closed , so that there is juice to the coil to fire the ignition.

On a magneto, there is only one terminal on the bottom of the switch. And the switch makes or breaks a connection between that terminal through its own case to ground. A single wire connects that terminal to the side of the magneto. In the down/stop position, the switch is closed, making a connection between the mag and ground, so it cannot run. In the up/run position, that connection is broken and the electrical system within the mag has no steady, unrestricted connection to ground, and is free to do its magneto thing.

Despite their quick-glance similarities, the two switches are entirely different animals.

You can make a distributor IH switch run a mag, but you can't make a mag switch run a distributor.

Mag switch = 1 terminal on the back
Dist. switch = 2 terminals on the back.

If you want to make a dist switch work with a mag, run 1 terminal wire to ground, and the other terminal wire to the mag. then, you will push it in to run, and pull it out to shut off. Kinda hokey, but I have done it in a pinch until I was able to get the correct switch.

so, depending upon what type of switch you are buying, will make a different only if you have a distributor ignition. If you have a mag, doesn't matter unless you want to be "correct".

HTH. IMHO.