Kohler — 4-Lead Separate Excitation
Testing & diagnosis · generator
From a Kohler service manual covering: 10RFY, 10RFZ, 10RY, 10RZ, 12R, 12RFY, 12RFZ, 18RFY, 18RFZ, 18RY, 18RZ. Check it applies to your exact model before use.
Applies to: Kohler 10RY, Kohler 12R, Kohler 18RY, Kohler 18RZ
Before you start
- Observe hazardous voltage precautions.
Procedure
- Disconnect all leads from voltage regulator.
- Connect DC ammeter, 10-amp fuse, and 12-volt battery to brush leads.
- Record ammeter reading; expected battery voltage divided by rotor resistance.
- Start engine and check ammeter remains stable.
- Check AC output across stator leads against specification.
- If rotor and stator test good, replace voltage regulator.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Ammeter reading = battery voltage / rotor resistance
Full service-parts list: Kohler 10RY →, Kohler 12R →
Source: Kohler service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.