Kohler — 4-Lead Voltage and Frequency Adjustment Procedure
Adjustments · PowerBoost IIIE voltage regulator
From a Kohler service manual covering: 10RFOY, 10ROY, 15RFOY, 15ROY, 6RFOY, 6ROY. Check it applies to your exact model before use.
Applies to: Kohler 10RFOY, Kohler 10ROY, Kohler 15RFOY, Kohler 15ROY, Kohler 6RFOY, Kohler 6ROY, Yanmar 3TN75E-RK engine, Yanmar 4TN84E-RK engine
Before you start
- Hazardous voltage; do not touch voltage regulator heat sink when testing.
Procedure
- Stop generator set; disconnect engine starting battery, negative lead first.
- Select desired voltage connection and connect leads according to the diagram.
- Turn voltage, Volts/Hz, and stability pots fully counterclockwise; turn remote rheostat to mid-point.
- Reconnect battery; move generator master switch to RUN to start generator set.
- Rotate voltage adjustment pot until desired output voltage is achieved.
- Rotate stability pot clockwise until minimum light flicker is obtained.
- Adjust engine speed to desired cut-in frequency (factory setting 57.5-58 Hz for 60 Hz models).
- Rotate Volts/Hz adjustment pot clockwise until voltage level begins to drop.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Cut-in frequency 57.5-58 Hz (60 Hz models) or 47.5-48 Hz (50 Hz models)
- Normal speed 63 Hz/1890 rpm (60 Hz) or 52.5 Hz/1575 rpm (50 Hz)
Full service-parts list: Kohler 10RFOY →, Kohler 10ROY →, Kohler 15RFOY →, Kohler 15ROY →, Kohler 6RFOY →, Kohler 6ROY →, Yanmar 3TN75E-RK engine →
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.