Severe weather and power outages can strike without warning—and when they do, your generator needs to be ready. If your FIRMAN portable generator will not start, runs briefly and shuts off, or won’t start on propane or natural gas, the steps below walk through the most common causes and fixes.

This guide applies to gasoline, dual-fuel, tri-fuel, and inverter models, including the FIRMAN whisper Series.

⚠️ Important Safety Reminder

Always operate your generator outdoors, far away from buildings, doors, windows, and vents.

If your unit shuts down shortly after starting and the CO indicator light is flashing, move the generator to a more open outdoor location and restart only after the alarm clears.

1. First-Time Starting Your Generator

If this is the first time you have used the unit, check the following:

Oil & Fuel

• Did you add the FULL bottle of oil?
  The low-oil sensor will prevent ignition if the level is too low.
• There should be more than 2 gallons of gasoline in the tank.
• Follow the step-by-step starting instructions in the owner’s manual.

Battery & Electrical

• Battery cables must be secure and in good condition.
• Ensure the quick-connect on the black negative cable is attached.
• Battery should measure 12.6V when fully charged.
• On inverter models, hold the battery restore switch for 3 seconds.

Switches & Valves

• Fuel valve in the “I” position.
• Ignition switch set to ON.
• On dual-fuel models, the fuel selector knob functions as the fuel valve.

Choke Procedure

• Try 1–2 starts with choke in START.
• If it does not fire, try 1–2 attempts with choke in RUN.

Spark Plug Check

• Ensure the spark plug wire is firmly attached.
• Remove the plug and perform a spark test by grounding it against the valve cover and pulling the recoil starter.
• If there is no spark, replace the plug.
• If spark is still absent, the ignition coil may need replacement and a certified service center can assist.

🔥 Starting on Propane (Dual-Fuel / Tri-Fuel Models)

• Make sure the propane tank valve is fully open.
• Propane is naturally harder to ignite than gasoline.

Tip:
Hold the start button while slowly moving the choke from START to RUN until the engine fires.

WHISPER Series Inverter Models

• Verify the power cable at the end of the regulator is fully connected.
• If disconnected, the solenoid will not open to allow fuel flow.
• Hold the battery restore switch for 3 seconds before starting.

2. Unit Has Been Used Before and Will Not Start

Re-check all items in Section 1, then continue below.

Oil Level

• Dip the dipstick without screwing it in to get an accurate reading.
• Change oil after the first 25 hours, then every 100 hours.

Air Filter

• Inspect for dirt, oil saturation, or blockage.
• Clean using warm soapy water, rinse, and allow to dry fully.

Spark Arrestor

• Located in the muffler.
• Should appear gray—not black or brown.
• If carbon-fouled, remove and clean with a wire brush or compressed air.

Inspect the Spark Plug for:

• Cracks
• Black, oily, or sooty deposits
• A rattling or “pinging” sound when shaken

Replace the plug if any of these are present.

Fuel Condition

• Gasoline should be no older than 1 month.
• Ethanol fuel can begin degrading in as little as 2–3 weeks.

If fuel has sat longer than 30 days:

• Carburetor jets or emulsion tubes may be clogged.
• Disassemble the carburetor and soak components in fresh gasoline for one hour.
• Thoroughly spray all orifices with carburetor cleaner.
• Contact FIRMAN Technical Support for further guidance.

3. Electric Start Does Not Work (But Recoil Does)

Battery & Restore Switch

• Battery must be charged.
• Hold restore switch for 3 seconds on inverter units.

Test the Start Switch

1. Remove the control panel to expose the rear of the switch.
2. Disconnect the wires.
3. Touch the wires together.
• If the unit starts → switch is faulty and should be replaced.

Check the Starter Solenoid

• Follow the battery cables to the cylindrical solenoid.
  • Pull back rubber boots on terminals.
  • Bridge terminals using a rubber-handled screwdriver.

  Results:

  • Engine cranks → solenoid is defective.
  • No response → battery voltage is insufficient and battery should be charged or replaced.

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  4. Unit Will Not Start on Natural Gas

  Confirm the following:

  • You are using a genuine FIRMAN Natural Gas hose kit (10 ft or 25 ft).
  • Hose must be ½-inch with a ⅜-inch female flare at the generator.
  • Supply requirements:
  • Maximum: 101,000 BTUs
  • Pressure: 0.25–0.40 PSI

  Home gas systems must meet these specifications—contact your gas provider or installer if unsure.

   

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  📞 Need Help? FIRMAN Technical Support Is Standing By

  If these steps do not get your generator running, our expert Technical Support team can help.

  📞 844-347-6261
  📧 info@firmanpowerequipment.com

  You can also use the live chat option on our website for real-time assistance with one of our support specialists.

  Support is available in English, French, and Spanish.