Read the manual thoroughly and understand all of the instructions, cautions, and warnings before using this equipment. If any section of the manual is not understood, contact your nearest authorized dealer, or contact Generac Customer Service at 1-888-436-3722 (1-888-GENERAC), or www.generac.com with any questions or concerns.  

Portable generator will not start

This article provides basic steps to troubleshoot a portable generator that will not start. End users may also reference the Portable generator troubleshooting quick reference guide for symptom-specific troubleshooting.

Environment

This article generally applies to Generac portable generators. You should always reference your generator owner's manual for the most accurate troubleshooting instructions for your specific model.

Troubleshooting (video)

Note: Do not start the generator under load. Before starting the unit, make sure there are no appliances or extension cords plugged into the generator.

Written instructions

1. Check and add the correct fuel

For gasoline (single fuel) generators: 

• Ensure there is at least a quarter tank of fuel to start the generator.
• Only use clean, fresh unleaded gasoline with a minimum octane rating of 87 and no more than 10% ethanol. Do not use E85, do not use an oil and gas mix. 
• If fuel has been stored in the generator for more than 30 days without fuel stabilizer, or more than 6 months with fuel stabilizer, then the carburetor may need to be cleaned: How do I clean my portable generator's carburetor?

For dual or tri-fuel generators:

• Verify fuel source meets the requirements specified in the owner's manual. Dual fuel generators running on liquid propane (LP) should only use 20 lb. propane tanks (the size commonly used for propane grills).
• Ensure proper fuel conversion procedures were followed: How to switch dual fuel portable generator between gasoline and liquid propane?
• Tri-Fuel generators running on natural gas must be properly connected to the natural gas (NG) fuel source and have correct fuel pressure. Reference your generator owner's manual for NG pipe sizing and fuel pressure requirements. 

Note: Starting a generator with NG fuel for the first time may take longer to crank in order to purge air out of the fuel hose. Repeated starts may be necessary. 

2. Set the fuel valve

• Ensure the fuel valve is in the ON position.
• Partially closing the fuel valve does not conserve fuel, it will only cause the engine to run improperly.

3. Check and fill the oil

• Ensure the generator is on level ground before checking the oil.
• Check the oil dipstick to confirm the oil is at a sufficient level.

4. Check the spark plug

• Make sure the spark plug wire is attached and secure. The boot should be pushed down and clicked into place over the spark plug (see image below).
• Replace the spark plug, if needed.

5. Set the choke

• For a warm, recently run unit, set it to half or no choke.
• For a cold unit, set it to full choke.

Note: If attempting to start the generator in cold conditions (under 32° F or 0°C) we recommend warming the generator in a heated garage or similar space for 24 hours prior to starting. Very cold temperatures can prevent portable generators from starting successfully. Before attempting to start the generator, relocate it outside in an open, unobstructed location far away from windows, doors, or vents. Never start a generator indoors.

6. Check the switch

• If your generator model has an ON/OFF switch, verify it's in the ON position.

7. Check the air filter

• Ensure it is clean and unobstructed. Replace if dirty or clogged: How do I inspect and clean my portable generator's air filter?

Additional troubleshooting

Electric start isn't working

• Verify the battery cables are securely connected and free of corrosion. Remove, clean, and reconnect battery terminals if necessary
• For models that support external battery charging, verify the battery is fully charged: Portable generator battery charging guidelines
• For models that do not support external battery charging, attempt to start the generator using the pull start. Then, when the generator is running, connect appliances to the generator and power them, which will charge the battery.

The cord is being pulled, but the engine will not rotate

• Remove the spark plug to release pressure built up in the engine.
• Alternatively, wait 30 minutes for the pressure to dissipate naturally.

Need additional support?

If the generator still does not start, contact Generac customer support at 888-436-3722. Or, contact a Generac Independent Authorized Service Dealer for assistance.