STIHL 017 018 021 023 025 MS170 MS180 MS210 MS230 MS250 Oil Drive Pump Worm Gear

Oil drive pump worm gear fits Stihl 017, 018, 021, 023, 025, MS170, MS180, MS210, MS230 and MS250 chainsaws. The worm gear sits on the crankshaft and meshes with the oil pump rotor to drive bar and chain oil through to the guide bar during cutting. On these Stihl consumer and semi-professional models the worm gear is a known wear item — stripped or worn teeth disconnect the oil pump entirely while the engine continues to run normally, making oil starvation easy to miss until visible damage appears on the bar rails or drive links. Inspecting and replacing the worm gear is the recommended first step when diagnosing a dry bar on these saws, before replacing the full pump assembly.

Fits the following Stihl models:

• Stihl 017
• Stihl 018
• Stihl 021
• Stihl 023
• Stihl 025
• Stihl MS170
• Stihl MS180
• Stihl MS210
• Stihl MS230
• Stihl MS250