Lessons learned substituting a cheap voltage regulator for the OEM one, which the company wants $120 for. You can pick up a number of regulators for approx $20. It turns out this is easy, except for one thing. Let me begin by telling the obvious stuff first. 1. Ya gotta match the voltages, natch. A 12v regulator to a 12v system. 2. You should match the current carrying capability of the regulator to that of the system rating. 20 amp regulator to a 20 amp alternator. 3. Now, you're going to have to know whether the system you're working on uses single phase alternators, or whether it uses a 3 phase alternator. Don't assume anything. Luckily, most lawn and garden tractor engines have single phase alternators. Many motorcycles and boat engines have 3 phase alternators. Then, you have to know for sure which kind of regulator you have (3 phase or single phase). I have no clue on this one, other than to find someone who knows, or go to the manufacturer and ask. If you know exactly what it is used on, that may lead you to answers on this question. 4. Wires. you can find all combos between 3 and 6 wire regulators. The good news is most of the lawn and garden tractor systems which have 4-6 wires can be worked with a 3 wire regulator. What happens is that, typically, there are warning indicator lights that each have a wire going to the regulator. You can simply disconnect these, and all you do is disable the warning light function. What the regulator has is two wires going to the alternator coil, and a wire going to the battery. Get those hooked up and you're in business. If your regulator has six wires out, that is almost sure to get all your functions operating, if your tractor pigtail is a 6 wire.