0J8478 0J8478S Air Filter - For Generac Generator Rectangle 14kW - 20kW 2013 Evolution Series - 2 Pack
Two rectangular orange air filters for Generac 14kW-20kW Evolution Series generators.
0J8478 rectangular air filter for Generac generator with labeled dimensions of 9.37 x 5.43 x 1.34 inches.
Infographic showing 0J8478 air filter for Generac generator with airflow and engine protection benefits.
0J8478 air filter replacement for Generac 14kW-20kW Evolution series generators shown with compatible generator unit.
Two rectangular air filters for Generac generators showing flexible material and pleated design.
Four-step installation guide for 0J8478 air filter on Generac Evolution Series generators.
Infographic showing 0J8478 air filter construction with close-ups of pleated paper media and flexible seal frame.
Compatibility chart for 0J8478 air filter listing compatible Generac generator models.
Compatibility chart for 0J8478 air filter showing compatible Generac generator models.
Two rectangular orange air filters for Generac 14kW-20kW Evolution Series generators.
0J8478 rectangular air filter for Generac generator with labeled dimensions of 9.37 x 5.43 x 1.34 inches.
Infographic showing 0J8478 air filter for Generac generator with airflow and engine protection benefits.
0J8478 air filter replacement for Generac 14kW-20kW Evolution series generators shown with compatible generator unit.
Two rectangular air filters for Generac generators showing flexible material and pleated design.
Four-step installation guide for 0J8478 air filter on Generac Evolution Series generators.
Infographic showing 0J8478 air filter construction with close-ups of pleated paper media and flexible seal frame.
Compatibility chart for 0J8478 air filter listing compatible Generac generator models.
Compatibility chart for 0J8478 air filter showing compatible Generac generator models.

0J8478 0J8478S Air Filter - For Generac Generator Rectangle 14kW - 20kW 2013 Evolution Series - 2 Pack

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$20.79
Sale $24.74
$20.79
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CONFIRM THIS PART FITS
Enter appliance or equipment model number to verify compatibility with this part

0J8478 / 0J8478S Air Filter

Key Features

  • Direct replacement air filter element for standby generators.
  • Protects the engine by filtering dust, dirt, and debris from intake air.
  • Designed to meet or exceed original equipment manufacturer (OEM) specifications.

Replaces / Cross-Reference Part Numbers

  • 0J8478
  • 0J8478S

Compatibility & Fitment

  • Brand: Generac
  • Engine Type: V-Twin
  • Engine Displacement: 990cc, 999cc
  • Generator Models: Fits most 14kW, 16kW, 18kW, 20kW, 22kW, 24kW, and 26kW air-cooled standby generators manufactured from 2013 to present.

When to Replace

  • Replace annually or as specified in your generator's maintenance schedule.
  • Inspect periodically and replace sooner if the filter is visibly dirty, clogged, or damaged.
  • A dirty air filter can lead to reduced engine performance and increased fuel consumption.

Installation Tips

  • Ensure the generator engine is off and cool before beginning.
  • Locate the air filter housing and remove the cover.
  • Remove the old filter and clean any debris from inside the housing.
  • Install the new filter, making sure it is seated correctly to form a proper seal.
  • Replace the air filter housing cover securely.
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  • FIXING SYMPTOMS

    FIXING SYMPTOMS

    Engine won't start | It starts, then stalls
  • DURABLE MATERIAL

    DURABLE MATERIAL

    This part is made of lightweight and robust aluminum alloy which is flexibility and flame-retardant, enhancing durability
  • BEST SOLUTION

    BEST SOLUTION

    Enjoy the great feeling when your generator is repaired and works like before - BlueStars brings DIY solutions to help you deal with any trouble
  • SIMPLE INSTALLATION

    SIMPLE INSTALLATION

    The Carburetor Kit is designed to be easily removed and replaced, allowing for quick and convenient maintenance
TRAP 99% OF AIRBORNE PARTICLES

TRAP 99% OF AIRBORNE PARTICLES

BlueStars Air Filter Kit effectively traps dirt and debris while maintaining airflow of the generator
MAXIMUM ENGINE PROTECTION

MAXIMUM ENGINE PROTECTION

By maintaining cleaner air intake, the 491588S helps improve fuel efficiency, reduces engine wear, and supports smoother operation
THE REPLACEMENT PART THAT KEEP YOUR YARD LOOKING FRESH!

THE REPLACEMENT PART THAT KEEP YOUR YARD LOOKING FRESH!

Compatible Models

Locate the model number of your appliance or equipment on the manufacturer's label and use it to check compatibility before ordering

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FAQs

This filter replaces part numbers 0J8478 and 0J8478S and is designed for 2013-and-later Evolution-series automatic standby generators in the 14kW-20kW range. It is also used on 14kW-22kW Evolution units equipped with 990cc, 992cc, or 999cc engines. Compatible brand families include Generac, Guardian, Centurion, Watchdog, Eaton, Honeywell, and Siemens. To confirm fit, match your existing filter number or your generator model and serial information to 0J8478 or 0J8478S.
This air filter is a direct replacement for Generac part numbers 0J8478 and 0J8478S. These are the primary numbers to verify for correct replacement fitment.
Typical signs include visible dirt loading, a dark or clogged filter element, reduced engine performance under load, harder starting, rough running, rich-smelling exhaust, or increased fuel consumption. On standby generators, replacement is recommended if the filter has been exposed to dust, debris, moisture, or rodent contamination inside the enclosure.
Air filter replacement on most Evolution-series standby generators is a straightforward maintenance task. It typically takes 5-15 minutes using basic hand tools, such as a screwdriver or nut driver, to open the air box. Always shut the generator down fully, disable automatic operation, and allow the engine to cool before service. Ensure the new filter is installed with the sealing surfaces properly seated to prevent unfiltered air from bypassing the element.
Before installation, inspect the air box for dust buildup, leaves, insect nests, or signs of water intrusion. Wipe out the housing, ensure the cover gasket and filter sealing edges are clean, and verify that nothing is blocking the intake path. If the old filter is heavily contaminated, it is also advisable to inspect the spark plugs and review the generator's regular maintenance schedule, as restricted airflow can affect combustion quality.
Early clogging is usually caused by dusty installation locations, landscaping debris near the enclosure, construction dust, long service intervals, or moisture contamination. Standby generators can accumulate dirt over time even with low run hours because they are exposed to the outdoors year-round during exercise cycles. Replacing the filter on schedule protects the engine from abrasive particles and prevents airflow restriction.