Generac QT 3.9L 40kW — Reconfigure the Fuel System (NG to LP)
Installation · Demand regulator / carburetor fuel system
For the Generac QT 3.9L 40kW, from the Generac owner's manual.
Applies to: Generac QT 3.9L 40kW, Generac QT Series, Generac V-type engine
Before you start
- Make sure fuel supply is of proper pressure and type for configuration.
- Keep ports free from debris during reconfiguration.
Procedure
- Turn the main gas supply off.
- Remove carburetor fuel hose from outlet Port 1 of demand regulator.
- Remove brass hose fitting from Port 1.
- Remove pipe plug from Port 2.
- Install brass hose fitting into Port 2.
- Install pipe plug into Port 1.
- Connect carburetor gas hose to brass fitting; tighten all clamps and plugs.
- Set the Dip switch inside the control panel to LP or NG position.
Tools required
- Pipe sealant Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Port 1 is for NG only; Port 2 is for LP vapor only
Full service-parts list: Generac QT 3.9L 40kW →, Generac QT Series →
Source: Generac owner's 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.