Operation Manual

32
English / USA
HT 250
If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
: Remove spark plug as described
in chapter "Starting / Stopping the
Engine".
: Clean dirty spark plug.
: Check the electrode gap (A) and
readjust if necessary – see
"Specifications".
: Use only resistor type spark plugs
of the approved range.
Rectify problems which have caused
fouling of spark plug:
: Too much oil in fuel mix.
: Dirty air filter.
: Unfavorable running conditions,
e.g. operating at part load.
Fit a new spark plug after approx.
100 operating hours
or earlier if the electrodes are badly
eroded.
To reduce the risk of fire and burn
injury, use only spark plugs
authorized by STIHL. Always press
spark plug boot (2) snugly onto
terminal (1) of the proper size.
(Note: If terminal has detachable
SAE adapter nut, it must be
attached.) A loose connection
between spark plug boot and
ignition wire connector in the boot
may create arcing that could ignite
combustible fumes and cause a fire.
If engine running behavior is
unsatisfactory even though the air filter
is clean and the carburetor and throttle
cable are properly adjusted, the cause
may be in the muffler.
Have your STIHL dealer inspect the
muffler for carbonization.
STIHL recommends that maintenance
and repair work be carried out only by
authorized STIHL dealers.
1
2
002BA071 KN
Engine Running Behavior