Genuine Tillotson HS-320A Carburetor for Stihl 066, MS650, MS660
Restore your chainsaw’s peak power with the Genuine Tillotson HS-320A Carburetor. Engineered for professional-grade performance, this carburetor is the preferred choice for loggers and arborists who require consistent fuel delivery and easy tuning on high-displacement Stihl saws. Tillotson carburetors are world-renowned for their precision machining and ability to maintain stable RPMs under heavy loads.
Professional Reliability
The HS-320A is designed to replace common factory units, offering a robust alternative to Zama and Walbro equivalents. It features a high-flow design that ensures your 90cc+ powerhead receives the exact air-fuel mixture needed for maximum torque during felling and bucking. Its durable construction is built to withstand the heat and vibration of daily professional use.
Product Specifications:
| Brand | Tillotson (Genuine OEM) |
| Model Number | HS-320A |
| Direct Fits | Stihl 066, MS650, MS660 |
| OEM Cross-Reference | Stihl 1122 120 0621 |
| Standard Replaces | Zama C3A-S31, Walbro WJ-67 |
⚠️ Installation Note:
Ensure your fuel lines and intake boot are in good condition before installing a new carburetor. A lean condition caused by air leaks can damage your engine, regardless of carburetor quality.
⚙️ Related Parts & Maintenance:
🛠️ Mechanic's Tip:
The Tillotson HS-320A is often the "fix" for saws that suffer from erratic idling with aftermarket or worn-out factory carbs. After installation, always perform a final tune (L, H, and Idle screws) once the saw is at operating temperature. If you are running a 32" or 36" bar, tuning slightly to the rich side can help protect your engine from overheating during long felling cuts.
Great Carb 
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