igintion

None that I'm aware of, but a starter solenoid with an IGN terminal, and a ballast-resistor in the coil primary circuit does essentially that.  Look at any automotive application of the 50's on, and if you see a ballast resistor in series with the primary circuit, you'll see that there's another wire... when the starter solenoid is energized, there's a bypass wire that feeds full available battery voltage to the coil, and when you release the key, the ballast resistor becomes the running current path.

Standard on new generation JD tractors. 6 volt coil with external resistor for 12 volts. A contact on the starter solenoid supplies 12 volts to the coil while cranking.

You don't need a diode, you need a relay. Something like the $3.95 cube relay sold at most auto stores will do just fine. Wire the coil in parallel with the coil on the starter solenoid (usually one side is grounded and the start switch or button supplies 12 volts). Wire one of the normally open contacts to the battery, and the other to the coil side of the resistor. Or more simply for the contacts, wire them so when energized, the relay shorts out the coil. If wired from the battery to the coil that will let the engine start when the ignition switch has gone bad but it stops as soon as you let off on the start button. My JD 4020 did that while making hay from bad wiring under the dash. I hot wired from the battery to the resistor to keep it running to finish the hay making. Then I removed the &*)(&(*^%$*&^%(*&%^ Scotch tap from the ignition circuit.

Gerald J.

Don't ya just love those Scotch loks?  LOL!  One of the main reasons why Trailer wiring doesn't work. Gotta' love these Trailer mfrs the way they wire their products. Cheap, cheap, cheap, fast, fast, fast, is the name of the game I guess. Quality gets tossed to the side, and after a year or so its fix, fix, fix...!!

MY STARTER IS WIRED FOR 28 VOLTS AND MY IGNITION IS ON 16 VOLTS  cause  the msd box cant handle more than 18 volts .  thats a 12 volt battery in series with a 16 volt race battery . The negative on the race battery goes to ground so I can wire the ignition box ground to the negative of the race battery and its positive post and have only 16 volts to the ignition. One set of cells .   can do the same with two six volt batterys . positive of one goes to the starter the negative of that battery goes to the positive of battery two .Battery twos negative goes to the tractor frame keep all 6 volt gauges and switches wired to battery two.

Edited by mlpankey - 17 Aug 2010 at 9:31am