Replacement Crankshaft for MS171 MS181 MS181C MS211 Models, Part No. 1139 030 0401 This replacement crankshaft restores the core rotational function of compatible small chainsaw engines. Designed as a direct fit for MS171 MS181 MS181C MS211 models, it provides a reliable solution when the original crankshaft is worn, damaged, or seized. Key benefits Direct replacement for Part No. 1139 030 0401 for MS171 MS181 MS181C MS211, ensuring correct fit and alignment. Restores engine crank motion and timing, supporting smooth starting and consistent power delivery. Sold as a single unit, simplifying repairs with one readytoinstall part. Reduces downtime during maintenance and repairs by matching original mounting points and dimensions. What it does Functions as the main rotating shaft that converts piston movement into engine crankshaft rotation. Supports connecting rod and piston operation, maintaining engine balance and performance. Package contents 1 x Crankshaft (works with MS171 MS181 MS181C MS211, replacement part number 1139 030 0401) Compatibility and fit Confirm compatibility with your machine model MS171 MS181 MS181C MS211 before . Matches the specified replacement part number 1139 030 0401 for straightforward installation. Typical use scenarios Repairing a chainsaw after crankshaft failure or excessive wear to restore normal engine operation. Rebuilding a used saw where internal components are replaced to bring the machine back to reliable working condition. Keeping on hand as a spare part for professional maintenance shops that service MS171 MS181 MS181C MS211 machines. Installation and care notes Inspect surrounding components such as bearings, seals, and connecting rod for wear when replacing the crankshaft. Professional installation or service fitment is recommended if specialized tools or alignment procedures are required. Verify part number 1139 030 0401 and model compatibility before installation to ensure correct fit.