Cleaning and Replacing Small Engine Air Filters

May 4, 2011



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Air Filter Care for Briggs and Stratton, Tecumseh Small Engines

Machine type: Mowers, Edgers, Roto Tillers, Grinders, Blowers

Brand: Craftsman, MTD, Toro, LawnBoy, Troybilt, Cub Cadet

Model number: Many

Related brands/models: Many

All power equipment, with the exception of snowblowers, has or should have air filters.

Without a filter, dirt will wear out the engine rings and valve seats and you will not like the result.  I was once advised by a small engine repair teacher that if a customer brings in an engine that has been run without a filter that I should decline working on it. He said that you could probably get it to run, but that the customer would never be satisfied with it after that.

My experience has been that he is mostly correct.

Dirty air will reduce compression and increase oil consumption. It will also increase spark plug fouling.  Mowers with these problems can still run, but save yourself a lot of grief by keeping your air filter in good shape.

Two things will make trouble for your air filter. First is just the dust. Dust will always be present when you are mowing.  When the dust builds up, it will decrease airflow to your engine.  This will make the engine run richer, have less power and if it gets bad enough, cause the engine to puff black smoke. This smoke is soot which is also fouling your spark plug.  A dusty air filter can usually be cleaned with compressed air.

The second is oil. If you tip the mower towards the air filter, engine oil can get to the paper element and plug it.  This can not be cleaned with compressed air but the filter will need to be replaced.

Step by Step Instructions for Air filter Care:

1.)    Find your air filter first.

On an Briggs and Stratton engine it will be to the left of the spark plug as you look at the spark plug from the front.

Briggs Air Filter Location

Briggs Air Filter Location

On a Tecumseh engine it will be on the rear of the engine on the right as your look at the spark plug.

Tecumseh Air Filter Location

Tecumseh Air Filter Locatio

2.)    The Briggs element is behind a plastic cover. Use a screwdriver or 5/16” socket to remove it.

Briggs cover removed

Briggs cover removed

The Tecumseh element is inside a perforated plastic cover. Turn the outer cover to unlatch three plastic hooks and pull the element and cover from the engine.

Tecumseh cover removed

Tecumseh cover removed

3.)   Pull and inspect the Briggs element from the plastic cover.

Briggs element pulled

Briggs element pulled

Pull the tubular paper element from Tecumseh plastic carrier.

Tecumseh pulled

Tecumseh pulled

4.)    Use compressed air to clean the elements.  I make sure to blow into each paper pleat and to gently bend the Briggs elemment to open up the pleats as I blow air into it. This is best done at the door of your garage as it gets dust everywhere.

Briggs cleaned

Briggs cleaned

5.)    If you do not have compressed air, or if the element is fouled with oil, just replace it. Notice how clean and pretty a new element can be:

New Tecumseh

New Tecumseh

6.)    Tecumseh engine will have a simple round element if they are a little older. Newer ones have a larger oval element in a larger housing. They both slip onto a neck on the carburetor and the cover slips over them. Be careful to line up the tab on the cover with the slot on the matching plate on the carburetor. Then the three latches will line up with cut outs on the carburetor and your can turn slightly to lock it into position.

Tecumseh mounting tabs

Tecumseh mounting tabs

For the Briggs engine, just place the element in the plastic cover with the wire mesh towards you and the paper pleats inward. Then line up the tabs on the cover bottom with the slots on the carburetor and swing it up and tighten the single screw.

7.)    Briggs engines with flat paper elements will have three possible sizes. One is square and is pretty rarely used. One is slightly rectangle and is the most common. One is clearly longer than it is wide and is also pretty rare.  I have also found that Honda slightly rectangular elements are the exact same size as Briggs and can work interchangeably.

The most common Briggs and Stratton paper element in my experience is this one: Item #1604599.  This is the longer, rarer one used on smaller HP engines: Item # 1604522.   This last one is rare, but I like to keep some on hand: Item #1604526. Tecumseh elements are these: Item #1606491 for the smaller, round one and this for the larger oval one: Item #1606499.

There are other elements used for larger and newer machines.  The principal is the same – get at it, inspect it and either clean or replace.  You will also see some foam precleaners. These catch some of the dirt and keep it from reaching your paper filter. These are cleaned with soap and water and re-oiled and will be the subject of a future article.

If you keep your engine oil changed, your air filter clean, your spark plug clean and in good shape and do not let mice build nests in your cooling fins, your engine should last for literally generations.

I worked on a Briggs and Stratton rotor tiller engine last fall.  The engine shroud numbers told me it was built in 1962. I put on a new carburetor and a modern magnatron ignition, cleaned the carbon and tightened the valves and it fired right up.

I suggest cleaning or replacing your air filter at the beginning of the mowing season and at least once part way through.  A visual inspection will tell you a lot at a glance.

Remember that annoying TV commercial for oil filters: The greasy mechanic says with a smirk: “You can pay me now, or your can pay me later” meaning an oil filter now, or a new engine later. An air filter now can give you an easy summer of mowing. A filthy air cleaner can make your engine run terribly, if at all, and maybe get you the experience many of my customers have had. I remove the ghastly paper element, clean the sooty spark plug, put on a fresh filter and start it right up.  I never act condescending and in fact am careful to preserve their self-respect.

You can preserve it for yourself and do-it-yourself.
Small Engine Filter Parts

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