Replaces Part Number: 1143-120-0641, 1143-120-0631, 1143-120-0611 carburetor. Replaces Zama C1Q-S295, C1Q-S296, C1Q-S233. Replace for 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, poor acceleration, and black smoke from the exhaust. This carburetor kit is made from premium materials and factory tested for reliable engine performance. Designed for easy installation and increased chainsaw service life. Value kit provides a cost-effective solution for routine maintenance and optimal performance. Components are simple to install, and installation videos are readily available online, typically taking 5–10 minutes. Note: This is compatible with the E-Z Starter version for Stihl MS251C chainsaw. If your MS251 model has a primer bulb, this is the correct carburetor kit. Slight physical color variations may occur due to lighting or display differences; this does not affect functionality. Color: As shown. Material: Metal. Package contents: 1 x carburetor kit. No other items included. Measurement tolerance: +/- 1–3 cm.