1. Introduction
This manual provides instructions for the proper installation, operation, maintenance, and troubleshooting of the Stens Air Filter, model 100-739. This air filter is designed as a direct replacement for Stihl OEM part numbers 4229 120 1800 and 4229 124 1500. It is compatible with various Stihl outdoor power equipment models, including BG45, BG46, BG55, BG65, BR45, SH55, and SH85. The air filter is constructed from woven fabric and includes an integrated pre-filter, designed to protect your engine from dust and debris, ensuring optimal performance and longevity.
2. Setup and Installation
Proper installation of the air filter is crucial for the efficient operation and protection of your equipment's engine. Always refer to your equipment's specific service manual for detailed instructions on accessing the air filter compartment.
Safety Precautions:
- Ensure the equipment is turned off and cooled down before beginning any maintenance.
- Disconnect the spark plug wire to prevent accidental starting.
- Wear appropriate personal protective equipment, such as gloves.
Installation Steps:
- Locate the Air Filter Cover: On your Stihl equipment (e.g., blower, shredder vac), identify the air filter cover, typically secured with clips or screws.
- Remove the Cover: Unfasten the clips or screws and carefully remove the air filter cover.
- Remove Old Filter: Gently pull out the old, dirty air filter. Note its orientation for correct installation of the new filter.
- Clean the Air Filter Housing: Before installing the new filter, clean any dust, debris, or dirt from the air filter housing using a clean cloth or compressed air. Ensure no debris falls into the carburetor intake.
- Install New Filter: Insert the Stens Air Filter 100-739 into the housing, ensuring it seats properly and securely. The woven fabric side should face outwards, towards the air intake.
- Replace Cover: Reattach the air filter cover and secure it with the clips or screws. Ensure it is tightly sealed to prevent unfiltered air from entering the engine.
- Reconnect Spark Plug: Reconnect the spark plug wire.
Image 1: The Stens Air Filter 100-739, a woven fabric filter with an integrated pre-filter, ready for installation.
3. Operating Principles
The air filter is a critical component of your outdoor power equipment's engine system. Its primary function is to prevent airborne contaminants, such as dust, dirt, and debris, from entering the carburetor and engine cylinders. By filtering the incoming air, the Stens Air Filter 100-739 helps maintain a clean fuel-air mixture, which is essential for efficient combustion, consistent engine performance, and preventing premature wear of internal engine components.
4. Maintenance
Regular inspection and timely replacement of the air filter are vital for the longevity and performance of your Stihl equipment.
Inspection:
- Inspect the air filter every 10-25 operating hours or more frequently in dusty conditions.
- Check for visible dirt, debris, tears, or damage to the filter material.
Replacement:
- Replace the air filter if it appears heavily soiled, clogged, or damaged. A clogged filter restricts airflow, leading to reduced engine power and increased fuel consumption.
- Even if it appears clean, replace the filter at least once per operating season or as recommended by your equipment's manufacturer.
- Do not attempt to clean heavily soiled paper or woven fabric filters, as this can damage the filter media and reduce its effectiveness. Replacement is the recommended action.
5. Troubleshooting
If your equipment experiences performance issues after air filter maintenance, consider the following:
- Reduced Engine RPM or Choking: If the engine does not reach full RPM or appears to be choking, the air filter might be too thick or improperly seated, restricting airflow to the carburetor.
- Incorrect Fit: Ensure the Stens 100-739 filter is the correct model for your specific Stihl equipment. An ill-fitting filter can lead to air leaks or excessive restriction.
- Improper Installation: Double-check that the filter is correctly oriented and fully seated within the air filter housing, and that the cover is securely fastened.
- Clogged Filter: A severely clogged filter, even if new, can cause performance issues. Verify the filter is clean and free of obstructions.
If troubleshooting steps do not resolve the issue, consult your equipment's main service manual or contact a qualified service technician.
6. Specifications
| Brand | Stens |
| Model Number | 100-739 |
| OEM Part Number (Replaces) | Stihl: 4229 120 1800, 4229 124 1500 |
| Compatible Stihl Models | BG45, BG46, BG55, BG65, BR45, SH55, SH85 |
| Filter Type | Woven fabric with integrated pre-filter |
| Product Dimensions (Approximate) | 25 x 25 x 15 inches (Packaging); 0.18 ounces |
| Fit Type | Vehicle Specific Fit |
| UPC / GTIN | 023899337088 |
7. Warranty and Support
For specific warranty information regarding your Stens Air Filter 100-739, please refer to the documentation provided with your purchase or visit the official Stens website. For technical assistance or further support, contact Stens customer service directly. Always provide your product model number (100-739) and the specific Stihl equipment model you are using when seeking support.
