Draining fuel from a portable generator
To prevent the fuel from expiring and causing starting issues in the future, it is recommended to drain all fuel from the tank of a portable generator or pump before storing it for more than 30 days.
Note: Generac support recommends that generators are run dry before storage. This ensures leftover fuel does not contaminate the carburetor.
Methods to drain fuel
The method to drain fuel will vary depending on the presence of a fuel shutoff switch.
Jump to:
Portable generators with a shutoff switch
Portable generators without a shutoff switch
Drain bolt specifications:
- 173cc, 196cc, 212cc Drain bolts are M10-1.25 thread pitch
- 389cc, 420cc, 459cc Drain bolts are M12-1.5 thread pitch
This applies to GP, XT, and RS series portable generators. For these models, enable the fuel shutoff valve and then remove the fuel hose and drain the remaining fuel from the tank.
1. Bring the unit into a well-ventilated area.
2. Open the gas tank cap to allow airflow through the tank.
3. Locate the fuel valve and turn it to the off position. The fuel valve is normally located just below the fuel tank.
4. Follow the fuel line from the shut-off valve down to where it connects to the carburetor (behind the air filter housing). Using a pair of pliers, pinch the hose clamp and slide it away from the carburetor.
5. Place an approved container next to the unit. Then remove the fuel hose from the carburetor and direct the hose into the container. If the fuel hose is not easily removed, try twisting it back and forth while pulling it away from the carburetor.
6. If needed, tilt the unit slightly so that all of the fuel goes to the end of the unit where the fuel valve is located.
7. Turn the fuel valve on to drain the fuel from the tank, being careful not to overfill the container.
8. When draining is done, turn the fuel valve back off and reconnect the fuel line to the carburetor, making sure to reinstall the hose clamp.
9. Next, locate the carburetor behind the air filter housing. Slide a container under the carburetor.
10. With the container in place, remove the carburetor’s drain bolt using a wrench or appropriate socket and ratchet. It will be the bolt that is positioned at an angle on the carburetor’s bowl, NOT the bolt at the very bottom of the bowl.
11. Allow any remaining gas to drain into the container. Replace the drain plug when complete.
12. Start and run the unit until all remaining fuel has been consumed.
This includes EFI (Electronic Fuel Injector) model generators. Portable units without a fuel shutoff switch must be siphoned. This will require siphoning tools which can be purchased from an auto parts store.
1. Bring the unit into a well-ventilated area.
2. Open the gas tank cap to allow airflow through the tank.
3. Insert the siphon and follow the siphon manufacturer's instructions to drain fuel from the tank.
