40027133017 Trimmer Head Spool Cap Cover - Fits Stihl Autocut 25-2 (FS90R, FS44, FS56, FS90 - 6 Pack

40027133017 Trimmer Head Spool Cap Cover

Key Features

• High-Durability Impact Polymer: Manufactured from specialized, glass-reinforced nylon designed to withstand high-velocity contact with rocks, curbs, and hard soil without cracking.
• Dual-Tab Locking System: Features a precision-molded snap-fit design that ensures the cap remains securely locked to the trimmer head even under high centrifugal force and heavy vibration.
• Optimized Ground-Slide Surface: The bottom profile is engineered for smooth "bumping" on the ground to advance line, reducing friction and extending the life of the internal spool components.
• Internal Spring Support: Designed with a centered recess to perfectly seat the AutoCut 25-2 internal spring, ensuring consistent tension and a reliable "snap-back" during line advancement.
• Heat-Resistant Engineering: Formulated to resist warping and melting caused by the friction heat generated during intensive, commercial-grade trimming and edging.

Replaces / Cross-Reference Part Numbers

• Stilh: 40027133017
  
• Stens: 385-563, 385-861
  

Compatibility & Fitment

This spool cap is the standard replacement for the Stihl AutoCut 25-2 trimmer head, which is found on a wide variety of professional and residential trimmers. Key compatible models include:

• Stihl FS Series (Small/Medium): FS 44, FS 55, FS 55R, FS 55RC, FS 56, FS 56C, FS 70, FS 70R.
• Stihl FS Series (Professional): FS 80, FS 83, FS 85, FS 87, FS 90, FS 90R, FS 94, FS 100RX, FS 110, FS 110R, FS 120, FS 130, FS 130R, FS 240, FS 240R.
• Stihl KM Series (Kombi): KM 55, KM 56, KM 85, KM 90, KM 110, KM 130 with trimmer attachments.
• Note: Specifically for the AutoCut 25-2 head. If your trimmer is equipped with the FixCut or PolyCut head, this cap will not be compatible.

When to Replace

• Worn-Through Bottom: The center of the cap has ground down from contact with pavement to the point where the internal spring is visible or the cap has become paper-thin.
• Broken Locking Tabs: One or both of the side "snap" tabs have cracked or snapped off, which can cause the cap and spool to fly off during operation.
• Visible Stress Fractures: Small white lines or cracks appearing in the black plastic, indicating the material has become brittle and is prone to failure at high RPMs.
• Loose Fitment: The cap no longer "clicks" firmly into the head housing, causing the internal spool to vibrate or the line to advance uncontrollably.
• Melting or Heat Damage: Significant warping of the plastic due to friction heat from the trimmer head or repeated contact with hot asphalt.

Installation Tips

• Clear the Debris: Before snapping on the new cap, use a stiff brush or screwdriver to remove dried grass, mud, and debris from the locking slots on the trimmer head housing.
• Check the Spring: Ensure the internal metal spring is seated flat and is not rusted or collapsed. A weak spring will cause the head to dump all the line at once.
• Tab Alignment: Align the two tabs of the cap with the corresponding notches on the trimmer head. Press down firmly on both sides simultaneously until you hear a distinct "click."
• The Manual Pull Test: After installation, give the cap a firm tug by hand to ensure both tabs are fully locked. A loose cap can become a high-velocity projectile at full throttle.
• Avoid Riding the Ground: To prolong the life of your new cap, try to keep the trimmer head slightly elevated. Only make contact with the ground when you need to "bump" for more line.