The Ultimate Guide to the Air Filter for Your Craftsman Push Mower
The air filter in your Craftsman push mower is a small, inexpensive part that plays a critical role in the mower's performance, longevity, and reliability. A clean and properly fitted air filter is the single most important component for protecting your mower's engine from premature wear and catastrophic failure. It acts as a barrier, preventing harmful dust, grass clippings, and debris from entering the engine's combustion chamber. Neglecting this simple part can lead to a cascade of problems, including hard starting, loss of power, excessive fuel consumption, rough idling, and ultimately, the need for expensive engine repairs or replacement. This comprehensive guide will provide you with everything you need to know about the air filter for your Craftsman push mower, from identifying the correct type to a detailed, step-by-step process for inspection, cleaning, and replacement, ensuring your mower runs smoothly for years to come.
Why the Air Filter is Non-Negotiable for Engine Health
A lawn mower engine, like any internal combustion engine, requires a precise mixture of air and fuel to operate efficiently. For every gallon of gasoline burned, the engine consumes an enormous volume of air. This air is drawn from the environment around your mower, which is often filled with fine dust, pollen, and tiny particles of grass and soil. Without an effective filtration system, these abrasive contaminants would be sucked directly into the engine.
Once inside, these particles act like sandpaper on critical engine components. They cause rapid wear on the cylinder walls, piston rings, and valves. This wear degrades engine compression, leading to a significant loss of power. Furthermore, debris can clog the small jets and passages in the carburetor, disrupting the delicate air-fuel ratio. A clogged air filter restricts the airflow, effectively choking the engine. This results in a mixture that is too "rich," meaning it has too much fuel and not enough air. This rich mixture does not burn completely, leading to black smoke from the exhaust, carbon buildup on the spark plug, and a noticeable decrease in fuel efficiency. In severe cases, a completely blocked air filter can prevent the engine from starting at all. Therefore, maintaining the air filter is not just a suggestion; it is a fundamental requirement for preserving the life and performance of your Craftsman mower.
Identifying the Correct Air Filter for Your Specific Craftsman Mower
Craftsman manufactures a wide range of push mowers with different engine models and horsepower ratings. Consequently, there is no single universal air filter that fits every machine. Using the wrong filter can result in poor sealing, allowing unfiltered air to bypass the filter element and enter the engine, causing the very damage you are trying to prevent.
The most reliable way to identify the correct replacement air filter is to locate your mower's model number. This number is typically stamped on a sticker or metal plate located on the mower's deck. Common places include under the seat, on the rear of the deck, or near the discharge chute. The model number will look something like "917.XXXXXX." Once you have this number, you can use it on the Craftsman parts website, at a local authorized service center, or at a retail store like Lowe's to find the exact OEM part. If you cannot find the model number, you can also search using your mower's engine model number, which is found directly on the engine. As a last resort, you can remove the old air filter and take it with you to the store to match it visually. The two most common types of air filters used in Craftsman push mowers are pleated paper filters and foam filters. Some models may even use a two-stage system that combines both.
Types of Air Filters: Pleated Paper vs. Foam
Understanding the type of air filter your mower uses is crucial for proper maintenance.
Pleated Paper Air Filters are the most common type found on modern Craftsman mowers. They consist of a cylindrical paper element with synthetic rubber seals on each end. The paper is pleated to create a large surface area for trapping microscopic particles. These filters are highly efficient at capturing fine dust and are designed to be replaced, not cleaned. Attempting to clean a paper filter with compressed air or tapping it can damage the delicate paper fibers, creating holes that allow dirt to pass through. Pleated paper filters should always be replaced, not cleaned.
Foam Air Filters are often found on older models or mowers designed for very dusty conditions. The foam is saturated with a special air filter oil. This oily foam acts as a sticky barrier, trapping dust and debris effectively. The primary advantage of a foam filter is that it is reusable. After it becomes dirty, it can be washed, re-oiled, and reinstalled. However, using a foam filter without the proper oil, or using too much oil, can be detrimental. A dry foam filter will not trap dirt effectively, and an over-oiled filter can allow excess oil to be drawn into the carburetor, potentially causing engine damage.
Two-Stage Air Filtration Systems offer the best protection. This system typically features an outer foam pre-cleaner that captures larger debris and an inner pleated paper filter that traps the finest dust. The foam pre-cleaner can be washed and re-oiled, while the inner paper filter must be replaced at the recommended service intervals.
Step-by-Step Guide to Inspecting the Air Filter
Regular inspection is the key to proactive maintenance. You should inspect your mower's air filter before the first use of the season and every 25 hours of operation thereafter, or more often if you mow in exceptionally dusty or dry conditions.
- Safety First: Before doing anything, ensure the mower is on a flat, level surface. Disconnect the spark plug wire from the spark plug. This is a critical safety step that prevents the engine from accidentally starting while your hands are near the moving parts.
- Locate the Air Filter Housing. The air filter is housed in a black plastic box, usually located on the side of the engine. It is often secured by a single wing nut, a screw, or a series of clips.
- Remove the Cover. Use your fingers or a screwdriver to loosen and remove the wing nut or screw. Carefully lift off the cover.
- Remove the Air Filter. Gently pull the air filter straight out of the housing. Take note of how it is oriented for correct reinstallation.
- Inspect the Filter. Hold the filter up to a bright light source. For a paper filter, look through the pleats. If you cannot see light clearly through a significant portion of the filter, it is time for a replacement. Check for any signs of damage, such as tears, holes, or deteriorated gaskets. For a foam filter, check if it is caked with dirt and oil. If it appears saturated with grime and is no longer a bright, porous foam, it needs to be cleaned or replaced.
A Detailed Guide to Replacing a Pleated Paper Air Filter
Replacing a paper filter is a straightforward process.
- Purchase the Correct Replacement Filter. Use your mower's model number to buy the exact OEM filter or a high-quality aftermarket equivalent.
- Follow Safety and Removal Steps. As described above, disconnect the spark plug wire and remove the old filter from the housing.
- Clean the Air Filter Housing. Before inserting the new filter, take a moment to clean the inside of the plastic housing. Use a clean, dry cloth or a soft brush to wipe away any loose dirt or debris. Be careful not to push any dirt into the intake tube that leads to the carburetor.
- Install the New Filter. Insert the new filter into the housing, making sure it sits flat and the rubber gaskets form a complete seal against the housing. There should be no gaps.
- Reinstall the Cover. Place the cover back on the housing and secure it tightly with the wing nut or screw. Reconnect the spark plug wire.
Your mower now has a fresh air filter, ensuring optimal engine protection.
How to Properly Clean and Re-oil a Foam Air Filter
Maintaining a foam filter requires a few more steps but is simple to do.
- Remove the Filter. Follow the safety and removal procedures outlined earlier.
- Wash the Filter. Wash the foam filter in a basin of warm water with a few drops of dish soap. Gently squeeze the foam repeatedly until the water runs clear and all dirt is removed. Do not twist or wring the foam, as this can tear it.
- Rinse Thoroughly. Rinse the filter under clean, running water until all soap residue is gone.
- Dry the Filter. Gently squeeze out excess water. Allow the filter to air dry completely. Never use a compressor to dry it, as this can damage the foam. Do not reinstall a damp filter.
- Re-oil the Filter. Once the filter is completely dry, pour a small amount of specialized air filter oil onto the foam. Work the oil evenly through the foam with your hands. The filter should be uniformly saturated but not dripping. If you squeeze it lightly, only a few drops should come out. Using motor oil or too much oil is a common mistake that can harm the engine.
- Reinstall the Filter. Place the freshly cleaned and oiled filter back into the housing and secure the cover.
Symptoms of a Dirty or Clogged Air Filter
Recognizing the signs of a failing air filter can help you address the problem before it causes serious engine damage. The most common symptoms include:
- Hard Starting: The engine cranks but struggles to turn over because the rich fuel mixture makes ignition difficult.
- Loss of Power and Performance: The mower feels sluggish, especially when going through thick grass or up a slight incline. It may bog down and stall.
- Black Smoke from Exhaust: This indicates a rich fuel mixture caused by insufficient air entering the engine.
- Excessive Fuel Consumption: The mower burns through gasoline much faster than usual because the inefficient combustion does not fully utilize the fuel.
- Rough Idling or Stalling: The engine may surge, sputter, or die when running at low speeds.
- Dirt Around the Air Filter Housing or Carburetor: This is a clear sign that unfiltered air is getting in, meaning the filter is damaged, incorrectly installed, or the housing is not sealed properly.
Frequently Asked Questions About Craftsman Mower Air Filters
How often should I change the air filter on my Craftsman push mower?
The general rule is to inspect the filter before each use and replace a paper filter or clean a foam filter every 25 hours of operation. However, if you mow in very dusty, dry, or sandy conditions, you may need to service it as often as every 10-15 hours. Always let the condition of the filter be your guide.
Can I use a foam filter on a mower designed for a paper filter, or vice versa?
No. You should always use the type of air filter specified by the manufacturer for your specific model. The air filter housing and intake system are engineered for a particular filter type and flow characteristic. Using the wrong filter can lead to inadequate filtration or restricted airflow.
Is it okay to use compressed air to clean a paper air filter?
It is strongly discouraged. Using compressed air on a paper filter can rupture the microscopic paper fibers, creating tiny holes that are invisible to the naked eye. Dirt will pass freely through these holes, defeating the purpose of the filter and leading to accelerated engine wear.
Where is the best place to buy a replacement air filter?
You can purchase genuine OEM Craftsman air filters from the manufacturer's website, Lowe's, or other authorized dealers. You can also find high-quality aftermarket filters from brands like Briggs & Stratton, STENS, and Oregon at lawn equipment repair shops, farm supply stores, and online retailers. Ensure the part number matches your mower's requirements.
What happens if I run my mower without an air filter for a short time?
This is extremely risky and should never be done. Even a few minutes of operation without an air filter can allow abrasive particles to enter the engine, causing immediate and irreversible damage to the cylinder walls and piston rings. The cost of a new air filter is minimal compared to the cost of an engine rebuild.
Conclusion: A Small Investment for Long-Term Reliability
The air filter is the guardian of your Craftsman push mower's engine. Its maintenance is one of the easiest, fastest, and most cost-effective tasks you can perform. By making a habit of regular inspection and timely replacement or cleaning, you are making a small investment that pays enormous dividends. You will enjoy a mower that starts easily, runs powerfully, uses fuel efficiently, and remains reliable for many mowing seasons. Keeping a spare air filter in your garage ensures you are always prepared to provide your equipment with the essential care it needs for a long and productive life.