The Kohler CH740/CH1000 is a 0.07 L 2-cylinder natural aspiration engine rated at 3600 rpm, producing up to 17.6 kW. It powers generator sets from Kohler, including the RDC2. It holds 1.9 L (0.5 gal) of oil.
Maintenance schedule
| Item | Spec | Capacity | Part # | Interval | |
|---|
| Air filter | | | — | | |
| Fuel filter | | | — | | |
| Oil filter | | | — | | |
| Battery | | | — | | |
| Belt | | | — | | |
| Coolant | | | — | | |
| Oil | | | — | | |
| Spark plug | | | — | | |
Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.
Procedures
10RDC2 Voltage Calibration Using SiteTech adjustment
Tools: digital voltmeter, personal computer, SiteTech software
- Connect PC to controller via USB
- With generator off, connect multimeter across L1/L2 (AC volts)
- Start generator set
- Compare voltmeter reading to controller display
- Calculate new Genset Calibration Factor Voltage using (Vmeter / Vcontrol) x Fold = Fnew
- Enter new value into SiteTech and click Apply Changes
- Verify voltmeter matches controller display
- Repeat for L2-L3 and L3-L1 if three-phase
- Press OFF to stop generator set
RDC2 Voltage Calibration Using the Controller Keypad adjustment
Tools: digital voltmeter
- With generator off, connect digital multimeter across L1 and L2, set to AC volts
- Start generator set with RUN button
- Navigate to Generator Metering menu, press Select; Volts L1-L2 displayed
- Press Select; voltage number flashes
- Use up/down arrows to match voltmeter reading
- Press Select to confirm
- Step to Return screen
- Press OFF to stop generator set
VSC Current (Load) Calibration Using the Controller Keypad adjustment
Tools: clamp-on DC current probe or DC current meter
- Connect DC current probe/clamp meter to measure generator current
- Start generator with RUN button
- Adjust system voltage to obtain rated current output with battery bank attached (or use load bank)
- Trip output breaker
- Navigate to Generator Metering menu, select Generator Load
- Press and hold Select for No-Load Calibration; verify breaker open, confirm Yes
- Close output breaker; verify rated output current, confirm Yes
- Verify displayed load is correct; recalibrate if necessary
- Press OFF to stop generator set
Firmware Update Using SiteTech maintenance
⚠ Do not load RDC2.4 firmware onto a red- or green-board controller
Tools: personal computer, USB cable, SiteTech software
- Download latest firmware file (.bin) from Kohler Power Resource Center or dealer portal
- Connect controller to PC via USB cable
- Start SiteTech; program recognizes connected device
- Click Update Firmware
- Browse to and select firmware file, click Open
- Verify current/new version and file name, click Update Firmware
- Wait for 'Firmware Updated Successfully' message, click Close
Setting the OnCue Password, RDC2 and VSC operation
- Press Select then down arrow to Networking Information menu
- Press Select for Networking Status
- Press Down arrow for Networking Configuration
- Press Select for Reset OnCue Password
- Press and hold Select until 'Reset OnCue Password? No' appears
- Press Up arrow to change No to Yes
- Press Select to reset; serial number and new password display for 10 seconds
Controller Replacement Procedure, Models 14RESA and 20RESA/B/C/D repair
⚠ Do not load settings from a green-board controller onto a red/blue-board controller or vice versa
Tools: voltmeter
- Review service kit information and confirm correct kits
- Open enclosure roof
- Press OFF button, disconnect utility power, verify with voltmeter
- Disconnect starting battery, negative lead first
- Remove two mounting screws, lift controller, disconnect harnesses
- Remove old controller
- If replacing original green-board controller with revised controller, install relay/breaker kit GM95104
- Reconnect harnesses, install new controller, reconnect battery negative last
- Reconnect utility power
- Set date/time/exerciser, update firmware, run Controller Setup and Voltage Calibration
- Replace covers/panels; reset OnCue password if used
Controller Replacement Procedure, Models 8/10/12RESV/L repair
⚠ Hazardous voltage can cause severe injury or death; disconnect all power sources before opening enclosure
⚠ Accidental starting can cause severe injury or death; disconnect battery cables, negative first
Tools: voltmeter, enclosure locking tool, screwdriver
- Open enclosure roof using locking tool
- Press OFF button on controller
- Disconnect utility power at building distribution panel; verify off with voltmeter
- Disconnect engine starting battery, negative lead first
- Remove two controller mounting screws and lift bottom edge of controller
- Note connections on back of controller, then disconnect all harnesses and leads
- Remove old controller
- Reconnect all harnesses to new controller assembly
- Install controller onto junction box with the two screws
- Reconnect battery, negative lead last
- Reconnect utility power by closing distribution panel breaker
- Set date/time and exerciser when prompted
- Check and update firmware to latest version via SiteTech or USB utility
- Perform Controller Setup (Section 5)
- Perform Voltage Calibration (Section 6)
Controller Replacement, Model RCL (RCL, RCLA, RCLB) repair
Tools: voltmeter
- Open/remove enclosure service door
- Press OFF, disconnect utility power
- Disconnect starting battery negative lead first
- Remove customer connection access panel, verify power off with voltmeter
- Remove two mounting screws, lift controller, disconnect P1/P2/P4/P5/P6
- Remove old controller, reconnect harnesses to new controller
- Install controller, replace access panel
- Reconnect battery and utility power
- Update firmware, set date/time/exerciser, run Controller Setup and Voltage Calibration
Controller Replacement, Models 14/20RCA/L repair
Tools: voltmeter
- Open enclosure roof, press OFF, disconnect utility power
- Disconnect starting battery negative lead first
- Remove two mounting screws, lift controller
- Verify utility power off at AC connections with voltmeter
- Disconnect harnesses, remove old controller
- Reconnect harnesses to new controller, install with screws
- Reconnect battery, reconnect utility power
- Set date/time/exerciser, update firmware, run Controller Setup and Voltage Calibration
VSC Controller Replacement, 6VSG repair
Tools: voltmeter
- Review service kit info, open enclosure roof
- Press OFF, disconnect utility power, verify with voltmeter
- Disconnect starting battery negative lead first
- Remove two mounting screws, lift controller, disconnect harnesses
- Remove old controller; if upgrading from green to revised board install relay kit GM92804
- Reconnect harnesses, install controller, reconnect battery negative last
- Reconnect utility power, update firmware
- Run Controller Setup and Voltage/Current Calibration
- Reset OnCue password if used
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Parts cataloged across the Kohler CH740 family
8| Part # | Description | Category |
|---|
| 223316 | Fuse, 10 A, 250 V | other_service |
| 292937 | Fuse, 20 A, 250 V | other_service |
| GM77569 | Original RDC2 | other_service |
| GM85969-1 | Controller, RDC2 - Distributor (original, discontinued, use GM92089) | other_service |
| GM90304 | Revised RDC2 Controller | other_service |
| GM92088-1 | Controller, RDC2 - Distributor (revised) | other_service |
| GM95149 | Diode Harness (for green-board controllers built before 9/15/14) | other_service |
| GM95500 | Battery charging diode harness field kit | other_service |
Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.
Common questions
What is the oil capacity of the Kohler CH740/CH1000?
The Kohler CH740/CH1000 engine has an oil capacity of 1.9 liters.
What is the displacement of the Kohler CH740/CH1000?
The Kohler CH740/CH1000 has a displacement of 0.0725 liters with 2 cylinders.
Which generators use the Kohler CH740/CH1000 engine?
The Kohler CH740/CH1000 powers 1 generator set(s), including Kohler RDC2.
What is a common problem with the Kohler CH740/CH1000 engine?
A commonly reported issue on generators using the Kohler CH740/CH1000 is: Under Voltage Paralleled. Fix: Press AUTO or OFF *.