The Kohler Command 20 horsepower V-twin engine is relatively simple to wire to your existing garden tractor or other equipment. The only wiring the engine really requires to run is 12 volts to the ignition system, which also energizes a fuel cut-off solenoid. If the equipment is more than five years old, it would be a good idea to replace the switches and other electrical components at the same time that you install the new engine. This will reduce the likelihood of electrical problems.
Things You'll Need
12-volt starting battery
6-gauge battery ground cable
2 battery starter cables, 6 gauge
20-amp fused 12-gauge insulated wire
18-gauge insulated wire
Wiring tool and terminal set
Connect a battery cable from the positive terminal of the battery to one of the studs on the starter relay. Connect the other battery cable from the other stud on the starter relay to the stud on the starter, which is on the engine.
Connect a fused 12-gauge wire from the positive terminal of the battery to the "Bat" terminal on the ignition switch.
Connect the red (ignition) and violet (regulator) wires from the engine to the "Ign" terminal of the ignition switch.
Connect the white (kill) wire from the engine to the "Off" terminal of the ignition switch.
Connect an 18-gauge wire from the "St" terminal of the ignition switch to the small terminal of the starter relay.
Connect the ground cable from the negative side of the battery to one of the mounting bolts on the base of the engine.
Do not connect the ground cable to the battery until you have checked your wiring.