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SOLVED! Briggs & Stratton Generator Bogs Down Under Load

Your generator isn’t giving you the power you’re used to. It has begun to bog down and run sluggishly.

Briggs & Stratton generators bog down and run 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.

Wait for the engine to cool and remove the spark plug wires before performing any repairs. Follow this in addition to the safety precautions outlined in the operator’s manual to minimize serious injuries.

Briggs & Stratton generator

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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 Briggs & Stratton Generator Bogs Down Under Load

1. Too Much Load is Applied for the Generator Size

Briggs & Stratton makes many different models with different limits to how much wattage a generator is able to handle. When you try to power more than it can handle, the generator will bog down and possibly shut down.

Adding too many items will not only cause your Briggs & Stratton to run sluggishly but it can also cause potential 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.

2. Dirty Carburetor

The carburetor’s job is to regulate the amount of fuel and air that gets mixed for combustion. Old fuel is often the reason a carburetor doesn’t function correctly causing the engine to bog down.

Old fuel can leave behind a varnish that will clog fuel passageways. Without sufficient fuel, the fuel and air mixture will not ignite to form the explosion needed to start the engine.

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 Briggs & Stratton carburetor if it still doesn’t function after cleaning it.

3. Clogged Fuel Filter or Sediment Bowl

A fuel filter is used on a Briggs & Stratton 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. You may also find a sediment bowl attached to the fuel valve. The filter can become plugged or the sediment bowl can become full causing a fuel restriction.

It’s best to replace the fuel filter or clean the sediment bowl each year when you are running your generator like most homeowners. If you use it more regularly, you must complete this maintenance more frequently.

If you are unsure if a fuel filter is used and where your fuel filter is located, contact a Briggs & Stratton service center for assistance.

4. Plugged 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 Briggs & Stratton operator’s manual.

I have included cleaning instructions for a couple of types of air filters below. Consult your operator’s manual if you are unsure of how to clean your type of air filter.

Clean a Briggs & Stratton 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.
  • NOT ALL FOAM FILTERS REQUIRE AN OIL APPLICATION. If yours does, saturate the filter in clean engine oil so it is fully covered. Then squeeze the filter to remove excess engine oil. You don’t want it dripping with oil.
  • Install the air filter.
  • Reattach the air filter cover.

Clean a Briggs & Stratton generator PAPER 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.
  • Remove the air filter and tap against a solid surface to knock dirt loose so it falls from the filter. Be careful not to damage the paper element.
  • Replace the air filter with a new one if you find the filter is very dark in color or damaged.
  • 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.

The choke is used to restrict air to the engine so the fuel runs rich with more fuel and less air. This is required to start a cold engine. The engine can bog down when the choke isn’t removed after starting.

This can be due to forgetting to adjust the choke to the off position once the engine warms. It may also be caused by a bad switch or dial (depending on your model) used to start the generator or a stuck choke.

6. Clogged Spark Arrestor

The spark arrestor screen is a part installed on a Briggs & Stratton 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.