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9
MS 311, MS 391
3.2
Chain Drive, Chain Brake, Chain Tensioner
Condition
Cause
Remedy
Chain sprocket wears rapidly
Chain not properly tensioned
Tension chain as specified
Wrong chain pitch
Fit chain of correct pitch
Insufficient chain lubrication
Check chain lubrication
Chain sprocket worn
Fit new chain sprocket
Saw chain stops under load at full
throttle
Clutch shoes badly worn
Install new clutch
Clutch drum badly worn
Install new clutch drum
Brake band blocked
Check freedom of movement and
operation of brake band
Saw chain rotates at idle speed
Engine idle speed too high
Readjust with idle speed screw
LA
(counterclockwise)
Clutch springs stretched or fatigued Replace the clutch springs or install
new clutch
Clutch spring hooks broken
Replace the clutch springs
Saw chain does not stop
immediately when brake is
activated
Brake spring stretched or broken
Fit new brake spring
Brake band stretched or worn
Fit new brake band
Clutch drum worn
Install new clutch drum