Stihl 009 Instruction Manual - Page 33

A factory new machine should not be run at high revs (full throttle off load) for the first three tank fillings. This avoids unnecessary high loads during the break-in period. As all moving parts have to bed in during the break-in period, the frictional resistances in the engine are greater during this period. The engine develops its maximum power after about 5 to 15 tank fillings. Always disengage chain brake before accelerating engine and before starting cutting work. High revs with the chain brake engaged (chain locked) will quickly damage the powerhead and chain drive (clutch, chain brake). A new chain has to be retensioned more often than one that has been in use for some time. Tension is correct when chain fits snugly against the underside of the bar and can still be pulled along the bar by hand. Retension if necessary see section "Tensioning the Saw Chain". The chain stretches and begins to sag. The drive links must not come out of the bar groove - the chain may otherwise jump off the bar. Retension the chain see section "Tensioning the Saw Chain". Always slacken off the chain after finishing work. The chain contracts as it cools down. If it is not slackened off, it can damage the crankshaft and bearings. • Slacken off the chain if you have retensioned it at operating temperature during cutting work. The chain contracts as it cools down. If it is not slackened off, it could damage the crankshaft and bearings. See chapter "Storing the Chain Saw". Allow engine to run for a short while at idling speed so that engine heat can be dissipated by flow of cooling air. This protects engine-mounted components (ignition, carburetor) from thermal overload.