Replaces Part Number: 1143-120-0641 1143-120-0631 1143-120-0611 carburetor. Replaces Zama C1Q-S295 C1Q-S296 C1Q-S233 and Walbro WTF-9 carburetor. Air filter tune up kit for Stihl MS231 MS231C MS231Z MS251 MS251C MS251CBE MS251C-BEQ MS251Z chainsaw (Primer Bulb Type). High-quality materials ensure smooth chainsaw operation, improved engine performance, and help resolve issues such as oil leakage, hard starting, lack of acceleration, and black smoke from the exhaust. Excellent quality construction with factory-tested components for reliable engine performance and easy installation. Designed to extend the service life of your chainsaw. Value kit provides a cost-effective solution for routine maintenance. Simple and user-friendly design; installation videos are widely available online and typically take 5–10 minutes to complete. Compatible with E-Z Starter Version for Stihl MS251C chainsaw. If your MS251 model has a primer bulb, this is the correct carburetor kit. Note: Slight physical color variations may occur due to lighting or display differences and do not affect functionality. Color: As shown. Material: Metal. Package contents: 1 x carburetor kit. Other products not included. Measurement error allowance: +/- 1–3 cm.