Chain Drive - Stihl MS 240 Instruction Manual

4.2 Chain Drive, Chain Brake, Chain Tensioner
Condition
Chain sprocket wears rapidly
Saw chain stops under load at full
throttle
Saw chain rotates at idle speed
Saw chain does not stop
immediately when brake is
activated
10
Cause
Chain not properly tensioned
Wrong chain pitch
Insufficient chain lubrication
Chain sprocket worn
Clutch shoes badly worn
Clutch drum badly worn
Brake band blocked
Engine idle speed too high
Clutch springs stretched or fatigued Replace the clutch springs or install
Clutch spring hooks broken
Brake spring stretched or broken
Brake band stretched or worn
Clutch drum worn
Remedy
Tension chain as specified
Fit chain of correct pitch
Check chain lubrication
Fit new chain sprocket
Install new clutch
Install new clutch drum
Check freedom of movement and
operation of brake band
Readjust with idle speed screw LA
(counterclockwise)
new clutch
Replace the clutch springs
Fit new brake spring
Fit new brake band
Install new clutch drum
MS 240, MS 260, MS 260 C