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This is Why Your DuroMax Generator Bogs Down Under Load

A generator with a starting problem often leaves you without a power source to run the items you need most.

A DuroMax generator bogs down and runs rough under load when too much load is applied for the size of the generator, the carburetor is dirty, the fuel filter is clogged, the air filter is plugged, the choke is stuck, or the spark arrestor is plugged.

Take safety precautions when working with your generator. This includes waiting for the engine to cool and removing the spark plug wire.


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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.

6 Reasons a DuroMax Generator Bogs Down Under Load

1. Too Much Load is Applied for the Generator Size

Not every DuroMax generator is the same. They vary in the amount of load the generator can handle.

When you try to power more than it can handle, the generator will bog down and possibly shut down.

Trying to power more items than the generator is designed to handle may not only cause the engine to run sluggishly but can also cause damage to the generator and the items connected to it.

Before checking the generator for items that can cause it to run rough, check the load limit of your generator along with the wattage requirements of the items you are running with the generator.

The wattage requirements of the items you are running at the same time must be less than the generator’s load limit.

Follow these tips to determine the wattage capacity:

  • You will find the wattage of most electrical items listed on a tag attached to the item.
  • Some motors require additional wattage to start an item. In this case, the starting wattage should be used when calculating wattage requirements. Your generator may have a starting wattage listed on the generator to temporarily handle the extra wattage requirement when an item is started.
  • Add the wattage of all items that will be plugged into the generator at one time to get a total.
  • This total wattage must be less than the generator’s wattage capacity.

Do not run more electrical items using the generator than it can handle. When the unit bogs down, shut down the generator.

Remove all items plugged into the ports. Restart the generator and add one item at a time and don’t go over the load limit.

2. Dirty Carburetor

When the carburetor isn’t able to regulate the amount of fuel that gets mixed with air for combustion, the generator will begin to bog down.

Carburetor failure is often the result of old fuel. Old fuel can leave behind a varnish that will clog fuel passageways.

Without sufficient fuel, the engine will run lean. A dirty carburetor will need to be removed to be cleaned or rebuilt to get working again.

To clean the carburetor, it’s a good idea to take photos through the disassembling process to make sure the small parts are placed in the correct positions when reinstalling the carburetor.

Remove the carburetor from the generator. Remove as much buildup as you can using a carburetor cleaner. If you find any damaged parts, use a carburetor rebuild kit to replace them.

Once cleaned and repaired, install the carburetor.

If working with small parts is not something you want to tackle, you can purchase and replace a complete carburetor instead of tearing it apart to clean and rebuild it. You may need a new carburetor if it still doesn’t function after cleaning it.

3. Clogged Fuel Filter

A fuel filter is used on a DuroMax generator to keep dirt from finding its way through the fuel system to the engine causing wear and damage.

You may have an inline filter placed between the fuel lines. If you don’t find a fuel filter, chances are the filter is installed at the bottom of the fuel tank or placed inside another fuel component.

If you are unsure if a fuel filter is used and where your fuel filter is located, contact a DuroMax service center for assistance. The filter may not be easily accessible and you may want assistance from a mechanic.

4. Clogged Air Filter

The air filter is an essential part to run on your generator. It ensures only clean air gets to the engine keeping out dirt and debris. Without an air filter, dirt can enter the air intake and permanently damage the engine.

I recommend replacing the air filter annually and more often when you use the generator more often than this or are using it in very dusty conditions.

In addition to replacing the air filter, you must also keep it clean. This includes checking the filter several times in between replacing the filter to ensure that the filter is kept in good condition and free of dirt and debris.

If you are not cleaning and replacing the filter regularly, the filter can become plugged with so much dirt that the engine won’t get sufficient air. It can cause the engine to bog down, overheat and cause extensive permanent damage.

Check the air filter before each use and clean or replace it if needed. Follow the cleaning instructions found in the DuroMax operator’s manual.

I have included cleaning instructions for a foam air filter below. Consult your operator’s manual if a different type of filter is used on your generator.

Clean a DuroMax generator FOAM air filter

  • Remove the air filter from the housing.
  • Wipe out any dirt remaining in the air filter housing and cover. Don’t allow dirt to fall into the air intake.
  • Inspect the foam filter for damage and replace it if needed.
  • If the filter is in good condition, clean it in soapy water and rinse it until the water runs clear.
  • Squeeze the filter and allow it to dry.
  • Coat the filter in clean engine oil so it is fully covered. Then squeeze the filter to remove excess engine oil. Absorbing excess oil with a paper towel works well too.
  • Install the air filter.
  • Reattach the air filter cover.

5. Stuck Choke

Another lack of airflow problem that can cause the generator to bog down is when the choke isn’t adjusted after the engine warms to allow sufficient air to get to the engine.

You will find a choke lever or choke knob on your generator used to restrict air to the engine so the fuel runs rich to start a cold engine.

When the choke isn’t removed after the engine warms, the engine will begin to run rough and possibly shut off because it’s not getting enough air.

If you still have an airflow problem after confirming you are using a clean air filter and properly set choke, you make have a stuck choke plate. In this case, use carburetor cleaner to help loosen the plate so it opens and closes when the knob or lever is adjusted

6. Clogged Spark Arrestor

The spark arrestor screen is a part installed on a DuroMax generator to prevent sparks and hot material from emitting from the muffler. This is to reduce burn injuries and potential fires.

When this metal screen becomes plugged with a buildup of carbon, the generator will begin to run rough and possibly shut down because hot exhaust air is unable to leave the engine.

Before removing and cleaning the spark arrestor, wait for the muffler to cool to reduce injury. Remove the spark arrestor screen and inspect its condition.

Replace the screen with a new one if you find any tears or holes in the mesh screen.

If the screen appears to be in good condition, clean it with a commercial solvent or brush it lightly using a small metal brush to remove soot deposits. Once the screen is clean, place it back onto the muffler.