Kohler — Fuel Conversion Procedure
Repair & overhaul · Fuel system (multi-fuel block)
From a Kohler service manual covering: 12RES, 8.5/12 RES, 8.5RES. Check it applies to your exact model before use.
Applies to: Kohler 12RES, Kohler 8.5RES, Kohler CH20 engine, Kohler CH 740 engine
Before you start
- Explosive fuel vapors can cause severe injury or death. Use extreme care when handling fuels.
Procedure
- Place generator set master switch in OFF; disconnect battery charger power.
- Disconnect the engine starting battery, negative lead first.
- Turn off the fuel supply.
- Remove the hose clamp and fuel hose from the hose fitting in the fuel block.
- Remove the hose fitting from the natural gas outlet port in the fuel block.
- Remove the plug from the LP port; clean, apply fresh pipe sealant, and install the plug into the natural gas outlet port.
- Clean the hose fitting, apply fresh pipe sealant, and install the fitting into the LP port.
- Slide the hose onto the hose fitting and secure it with the clamp.
- For the 12RES only: connect the DSAM leads together for natural gas (disconnect for LP).
- Connect and turn on the new fuel supply.
- Reconnect the battery, negative lead last; reconnect power to the battery charger.
- Start the generator set by moving the master switch to RUN.
- Check for leaks using a gas leak detector.
- Move the generator set master switch to the AUTO position.
Tools required
- gas leak detector Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Do not adjust the fuel metering valves.
Full service-parts list: Kohler 12RES →, Kohler 8.5RES →
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.