Why is oil coming out of my air filter on my lawn mower?

Asked By: Razvan Klausjurgens | Last Updated: 8th February, 2020
Category: home and garden home appliances
4.7/5 (3,403 Views . 23 Votes)
An air filter consistently clogged with oil is most likely the result of turning the mower over the wrong way when you work on the blades underneath the mower deck. If you turn the mower over with the air filter down, the engine oil will leak out and into the filter, clogging it.

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Regarding this, why is oil coming out of my carburetor on my lawn mower?

A blown head gasket is one such issue, and it requires tear down, repair and reassembly of the lawnmower's engine. Other internal engine possibilities causing the oil problem include a damaged cylinder or worn cylinder rings. If they fail, oil can back up through the carburetor and into the air filter.

Also Know, what happens if I put too much oil in lawn mower? Too much oil in the crankcase can damage the motor of the lawn mower. Too much oil can also cause the lawn mower to leak which can damage other parts of the lawn mower other than its motor. This is a classic case of when too much or too little can affect how an engine works.

Likewise, people ask, why would gas come out of the air filter?

The carburetor float can become permanently stuck in the open position, which allows gas to flow up through the air filter and out of the mower. This is usually a sign of dirty fuel. Cleaning the float and carburetor and replacing or cleaning the fuel filter can help resolve this problem.

What are the symptoms of a blown head gasket in a lawn mower?

Signs & Symptoms of a Blown Lawn Mower Head Gasket

  • Low Power. Low engine power in a lawn mower can be caused by wear and tear, lack of oil or regular maintenance, worn-out seals or a blown head gasket.
  • Failed Compression Test.
  • Diminished Compression.
  • Oil Leak.

28 Related Question Answers Found

Why is my Briggs and Stratton leaking?

A damaged upper bearing ring seal will cause oil to leak from the top of the crankcase while the engine is running. If there is a buildup of oil around the seal, or if the seal itself is noticeably worn, the upper bearing ring seal is likely the cause of the oil leak.

How do I clean the air filter on my Briggs and Stratton lawn mower?

Cleaning a Foam Air Filter
  1. Turn off the engine of a riding lawnmower and engage the parking brake.
  2. Lift out the foam filter.
  3. Dab the filter with clean motor oil.
  4. Clean any debris from the rubber gasket that seals the air filter to the carburetor.
  5. Put the filter back into place and replace the housing.

Where is the crankcase breather located on a Briggs and Stratton?

Locating the Crankcase Breather
Briggs & Stratton lawnmowers will typically have the breather mounted near the rear of the engine, but other makes may have the breather mounted on the right or left side or even at the front of the engine.

How much oil does a Briggs and Stratton lawn mower take?

Briggs & Stratton 5W-30
of oil is required for the I/C (Industrial/Commercial) engine. Note: Two bottles are required to meet your oil capacity. 18 oz. of oil is required for the Classic engine.

What does it mean if there's oil in the air filter?


Oil in the air filter is an indication that there's a blow-by problem. The first culprit to check is the PCV valve. If it is blocked or only semi-functional, replacing the valve and cleaning the system is usually all that's necessary to fix the situation.

How do you get oil out of paper air filter?

Soak air filter well in gas. Ignite gas to remove oil. Toss burning air filter onto grass. Oil will be removed from filter and grass will burn down to ground level.

Can you clean a lawn mower air filter?

To clean a foam air filter, follow these steps:
Turn off the lawn mower, or make sure to pull the spark plug before all else and have it cooled down. Unscrew the housing where the air filter is located. Pull out the air filter and wash with hot water and liquid soap to cut the grease.

Can you run a lawn mower without an air filter?

It isn't good for the lawn mower to keep running it with the filter removed, however, because the engine actively draws air through the intake port, and without the filter, the piston cylinder can be quickly contaminated by particles that can damage the piston seals.

What happens when you tilt a lawn mower?

If you tip the lawn mower the wrong way, the fuel in the carburetor can easily leak into the air cleaner which will cause problems to the combustion system. When fuel leaks into the engine, it leads to too much fuel which the lawn mower engine cannot burn.

How often should you change your lawn mower air filter?


If you have a combination air filter with pre-cleaner, replace pre-cleaner every 25 hours or every season, and replace cartridge every 100 hours. If you do not have a pre-cleaner replace cartridge every 25 hours or every season, more often under dusty conditions.

Can a dirty air filter cause a lawn mower not to start?

Starting Trouble
Air, Fuel, and Spark. Without one of these components your engine will never start. So, if your air filter isn't providing the right amount of air flow into the mixture, your equipment will stall, surge, and sputter as it gasps for air.

Why is my lawn mower blowing out white smoke?

A lawn mower that is putting out white smoke usually indicates an engine that is burning oil. Overfilling the oil or an excess of oxygen within the engine usually causes this. White smoke can also be caused by incorrect oil grades, air leaks, worn cylinder/rings or a blown head gasket.

How does gas get into oil on lawn mower?

What causes fuel to leak into my engine oil? The fuel shut-off valve isn't closed properly. Fuel float in the carburetor being stuck in the open position due to gumming (caused by stale fuel) or debris.

How do you seal a gas tank on a lawn mower?

How to Repair a Black Plastic Lawn Mower Gas Tank
  1. Drain the tank of any residual gas.
  2. Sand the area that needs to be repaired with the sandpaper that comes with the kit.
  3. Cut the enclosed fiberglass repair patch to fit the area, using scissors.
  4. Mix the two-part adhesive compound together from the tubes in the repair kit.

What causes gas to leak from a carburetor?


Small Engine Carburetor Issues
Another common cause of gas leaking around air filters is due to carburetor issues. Cleaning or replacing your carburetor or fuel float may be necessary, but make sure to understand how to troubleshoot or service carburetors before taking action.

What causes gas to pour out of carburetor?

Sometimes the fuelcock diaphragm will wear out and allow fuel to flow to the carburetor when the unit is shut down, which will cause excess fuel to dump out the overflow tube. Replace the fuelcock would be the way to go. Now lets say that it is hooked up right, fuel flows into the float bowl from the gas tank.

Why does gas leak from carburetor?

Common Carburetor Fuel Leaks. When the tip of the valve becomes worn or debris prevents the closing of the valve, fuel flows continuously into the bowl thus flooding the engine. Under severe conditions gas may soak the air filter or overflow out of the carburetor and onto the ground while parked.