Stihl HT 75 Instruction Manual - Page 28

Operating Instructions, During break-in period, During operation, After finishing work

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Operating Instructions english During break-in period 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. Do not make the mixture leaner to achieve an apparent increase in power - this could damage the engine - see chapter "Adjusting the Carburetor". During operation Check chain tension frequently! A new chain has to be tensioned more often than one that has been in use for some time. Cold chain Tension is correct when the chain fits snugly against the underside of the bar and can still be pulled along the bar by hand. Retension if necessary - see chapter "Tensioning the Saw Chain". Chain at operating temperature The chain stretches and begins to sag. The drive links on the underside of the bar must not come out of the bar groove - the chain may otherwise jump off the bar. Retension the chain - see chapter "Tensioning the Saw Chain". Always slacken off the chain again after finishing work. The chain contracts as it cools down. If it is not slackened off, it may damage the crankshaft and bearings. After a long period of full-throttle operation Allow engine to run for a while at idle speed so that the heat in the engine can be dissipated by flow of cooling air. This protects engine-mounted components (ignition, carburetor) from thermal overload. After finishing work : 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 may damage the crankshaft and bearings. Wait for engine to cool down. Drain the fuel tank. Store the machine in a dry place. Check tightness of nuts and screws (not adjusting screws) at regular intervals and retighten as necessary. HT 70, HT 75 27

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27
HT 70, HT 75
english
During break-in period
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.
Do not make the mixture leaner to
achieve an apparent increase in
power – this could damage the
engine – see chapter “Adjusting the
Carburetor”.
During operation
Check chain tension frequently!
A new chain has to be tensioned more
often than one that has been in use for
some time.
Cold chain
Tension is correct when the chain fits
snugly against the underside of the bar
and can still be pulled along the bar by
hand.
Retension if necessary –
see chapter “Tensioning the Saw Chain”.
Chain at operating temperature
The chain stretches and begins to sag.
The drive links on the underside of the
bar must not come out of the bar groove
– the chain may otherwise jump off the
bar.
Retension the chain –
see chapter “Tensioning the Saw Chain”.
Always slacken off the chain again
after finishing work. The chain
contracts as it cools down. If it is not
slackened off, it may damage the
crankshaft and bearings.
After a long period of full-throttle
operation
Allow engine to run for a while at idle
speed so that the heat in the engine can
be dissipated by flow of cooling air. This
protects engine-mounted components
(ignition, carburetor) from thermal
overload.
After finishing work
:
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 may damage the
crankshaft and bearings.
Wait for engine to cool down. Drain the
fuel tank. Store the machine in a dry
place. Check tightness of nuts and
screws (not adjusting screws) at regular
intervals and retighten as necessary.
Operating Instructions