Troubleshooting Chart; Chain Brake; Chain Tensioner - Stihl MS 440 Service Manual

4.

Troubleshooting Chart

4.1 Clutch, Chain Drive, Chain Brake,

Chain Tensioner

Condition
Saw chain stops under load at full
throttle
Saw chain rotates at idle speed
Loud noises
Chain sprocket wears rapidly
Saw chain does not stop
immediately when brake is
activated
MS 440, MS 440 C
Cause
Clutch shoes badly worn
Clutch drum badly worn
Brake band stuck
Engine idle speed too high
Clutch springs stretched or fatigued Replace clutch springs
Clutch spring hooks broken
Clutch springs stretched or fatigued Replace all clutch springs
Needle cage damaged
Clutch shoe retainer broken
Clutch shoes and carrier worn
Chain not properly tensioned
Wrong chain pitch
Insufficient chain lubrication
Chain sprocket worn
Brake spring stretched or broken
Brake band stretched, worn or
broken
Remedy
Replace clutch shoes
Install new clutch drum
Check freedom of movement
and function of brake band.
Adjust idle speed screw
(counterclockwise)
Replace clutch springs
Fit new needle cage
Fit new retainer
Install new clutch
Tension chain as specified
Fit chain of correct pitch
Check chain lubrication
Fit new chain sprocket
Fit new brake spring
Fit new brake band
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