Instruction Manual

43MS 290, 310, 390
English / USA
Erratic idling behavior, poor
acceleration
Idle setting is too lean.
: Turn the low speed adjusting screw
(L) counterclockwise until engine
runs and accelerates smoothly.
Adjustment for operation at high
altitude
A slight correction of the setting may be
necessary if engine power is not
satisfactory when operating at high
altitude:
: Check standard setting.
: Warm up the engine.
: Turn the high speed adjusting screw
(H) and low speed adjusting screw
(L) clockwise (leaner)
If you make the setting too lean, the
maximum permissible engine speed
will be exceeded – risk of engine
damage.
If the engine is low on power, check the
spark arresting screen inside the muffler.
: Take off the nuts (1).
: Remove the cover (2).
: Remove the spark arresting screen
(3).
: Clean spark arresting screen if
necessary.
: If screen is damaged or coked up,
fit a new one.
: Refit the spark arresting screen –
fit the cover.
* see “Guide to Using this Manual”
H
L
LA
139BA013 KN
4
L
H
3
1
/
4
/
Spark Arresting Screen in
Muffler*
1
1
1
139BA020 KN
139 BA021 KN
3
2