Trimmer Gear Head Replacement for Stihl FS Series - Direct Fit Gearbox

In this review the reviewer examines the Yutacorex replacement gear head designed for a wide range of Stihl FS and FR series brushcutters, including FS91, FS111R, FS131 and many more. The bottom line: this gearbox replacement is for homeowners and maintenance pros who need a direct-fit, lightweight replacement that includes all small parts to restore a worn or damaged gear head assembly. The review finds the unit well suited for routine repairs where matching the listed model numbers is confirmed before purchase.

Key Features

• Complete replacement kit: Includes the gear head, thrust plate, thrust washer, rider plate, collar nut and five stainless screws so you have the components needed for reassembly.
• Direct compatibility: Replaces part number 4180 640 0114 and associated thrust and rider components, which makes it easy to match to many Stihl FS and FR models.
• Lightweight construction: The gear head is described as lighter weight, which can reduce front-end load on a handheld trimmer during extended use.
• Sturdy fasteners: Supplied stainless steel screws resist corrosion and provide stable clamping for outdoor use.
• Flexible blade exchange: The design allows straightforward swapping of weed eater blades or heads, simplifying field repairs.

Who It's For

This replacement gear head is intended for people who already own compatible Stihl trimmers and need a straightforward gearbox swap to restore function. It suits homeowners, landscapers and repair technicians who can confirm model compatibility and who are comfortable performing a mechanical replacement using supplied parts.

People who should look elsewhere include owners of trimmers with nonmatching stamped part numbers or unique backpack models with a different bottom decorative fit, and users expecting a factory-original branded part without aftermarket differences.

Pros & Cons

Pros

• Complete kit contains all small parts, reducing the need to source extras.
• Matches a wide range of Stihl FS and FR series numbers, making it versatile for repairs.
• Stainless screws and lightweight gear head balance durability and reduced weight.

Cons

• Must confirm model match before ordering because some backpack or specialty bottoms differ.

Specifications

Our Verdict

This replacement gear head is a practical value for anyone who confirms fit with the listed Stihl model numbers and wants a ready-to-install kit. It delivers necessary hardware, corrosion-resistant screws and a lighter assembly that makes installation and blade exchange easier, though buyers should verify the bottom decorative and backpack differences before purchasing.

Frequently Asked Questions

Will this fit my Stihl FS240?
Yes, FS240 and many FS/FR models are listed as compatible, but you must confirm the stamped part number matches before ordering.

Does the kit include mounting screws?
Yes, five stainless steel screws are included along with the collar nut and internal plates needed for assembly.

Is the collar nut standard thread?
The supplied collar nut is M10x1 left hand thread, matching the original specified part.