860 Starter Solenoid

Looked in the archives and couldn't find anything there.
Thanks,
Don

On a X00 tractor they use a 3 post relay.
The small post gets hooked to the starter button on the trans. The relay gets its power from a internal jumper to the battery side of the relay.
This is why you have to hook the battery to the correct side of the relay for it to work.
The problem with this relay is you can crank the tractor with out having the key on. It will not start because the key provides power to the coil; but it is still dangerous around children.

Now we go to the X01 tractors. We now have to deal with diesel motors so we need a relay that will not work with the key off. So the relay was changed to a 4 post relay. Instead of getting its power from a internal jumper the power is now supplied via the key to one of the small post. The other small post gets hooked to the starter button on the trans.

Now we move on to the 1965 and newer tractors. These tractors use the same relay as the cars do.
The S post is hook to ground internally so you do not need the starter button on the trans. When you supply power to the S post from a dash mount starter button or by using a key with a start position the motor will crank. The I post is hook to the output or starter side of the relay via a internal connection. It only gets power while cranking so we can hook a wire from here straight to the coil to bypass a inline resistor that is in the wire from the key to the coil. This bypass supplies a full 12 volts to the coil while cranking for easy starting. Once the tractor starts this connection is broken so the coil needs to get its power from the key via the inline resistor preventing the coil from burning up from to many volts.

Any help would be appreciated.

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