Diagnosis
Excessive vibration indicates an imbalance in the rotating assembly or loose components. The primary suspect is a damaged or heavily unbalanced chain.
How to Fix It
First, stop the saw. Remove the chain and inspect it for a damaged or missing cutter, a stiff or frozen link, or severe uneven wear. Spin the chain by hand on a flat surface to check for bends. Replace the chain if any defects are found.
If That Didn't Work
With the chain and bar removed, start the saw briefly. If vibration is still high, the issue is internal. Likely causes are a bent crankshaft, failed engine mounts, or a loose flywheel. This requires professional service.
Heads Up
Never operate a chainsaw with a badly vibrating chain. It dramatically increases the risk of kickback and causes premature failure of the crankshaft bearings.