coil replaceing on 3020

MSS3020 · Sep 25, 2012

Replaced the coil on my 3020. Old coil according to
the manuel has a resistor wire that runs from the
coil to someplace up behind the engine. The new coil
says doesnt require outside resistor. So do I need
to find that resistance wire and do what with it..
or can it just stay..

Walt Davies · Sep 25, 2012

That wire runs from the coil to the key switch. The wire should be stiff.
Walt

David G · Sep 25, 2012

Is there also a bypass wire for starting?

wisbaker · Sep 25, 2012

Here's the problem if you have TWO wires going to the coil on one side and one wire going from the coil to the distributor you have a start by-pass. One of those wires is only hot when you have the starter energized (full 12V)and the other one (the resistor wire or 6V) is hot when the key is on. If you use the regular wire your tractor will only run when you have the starter engaged/powered, if you use the resistor wire your coil won't be getting the 12V it needs to work properly so you'll always be fighting weak spark. So you're going to have to replace the wire from the key switch to the coil (resistor wire)with a regular wire or get the right coil. If it were mine I'd get the right coil, don't have to butcher up the tractor wiring and John Deere did know what they were doing, the way they built it you have "hotter" spark to help starting. You've eliminated that with the high resistance coil

David G · Sep 25, 2012

Wisbaker is right if it has a bypass, get the right coil or you will screw up cold weather starting.

John T · Sep 26, 2012

If it has an external voltage dropping (12 to 6) ballast wire/resistor/link then you need a 6 volt coil. That will be a coil labeled "6 volts" or "12 volts for use with/requires external ballast" but NOTTTTTTTT one labeled "12 volts NO Ballast required/used" cuz that coil requires 12 NOT 6 volts......

If you use a coil thats designed for full 12 volts on a system that has a voltage dropping external ballast resistor (i.e. only puts 6 to the coil) you get a weak spark.

So if your new coil says 12 volts and doesnt require outside resistor yet the tractor uses an external/outside voltage dropping (12 to 6) resistor YOU WILL GET A WEAK SPARK. Again, you would need a 6 volt or "12 for use with/requires ballast resistor" coil for proper operation. If you tractor does NOT use any external voltage dropping ballast resistor, then you need a 12 volt coil (i.e. one labeled 12 volts or 12 volts not for use with resistor)

John T

coil replaceing on 3020

MSS3020

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Walt Davies

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David G

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wisbaker

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David G

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John T

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