Stihl 017 Instruction Manual - Page 34

Chain Brake The chain brake is also activated by the inertia of the front hand guard if the kickback force of the saw is high enough: The hand guard is accelerated toward the bar nose - even if your left hand is not behind the hand guard, e.g. during felling cut. The chain brake will operate only if the hand guard has not been modified in any way. Locking chain with chain brake - in an emergency - when starting - at idling speed. • The chain is stopped and locked when the hand guard is pushed toward the bar nose by the left hand or when brake is activated by inertia in certain kickback situations. 143BA011 KN 143BA012 KN Releasing the chain brake • Pull the hand guard back toward the front handle. Note: Always disengage chain brake before accelerating engine and before starting cutting work. The only exception to this rule is when you check operation of the chain brake. High revs with the chain brake engaged (chain locked) will quickly damage the powerhead and chain drive (clutch, chain brake). Check operation of chain brake Before starting work: Run engine at idle speed, engage the chain brake (push hand guard toward bar nose). Accelerate up to full throttle for no more than 3 seconds - the chain must not rotate. The hand guard must be free of dirt and move freely. Chain brake maintenance The chain brake is subject to normal wear and tear. It must therefore be checked and serviced regularly by trained personnel (e.g. STIHL dealer) at the following intervals: Full-time professional users: every 3 months Semi-professional users: every 6 months Occasional users: every 12 months 32 017, 018