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Carburettor adjustment
T: Idle speed adjuster
L: Low speed mixture adjuster
H: High speed mixture adjuster
Every unit is test run at the factory and the carburettor is fine tuned for maximum performance.
Any change from this setting should be performed only with the aid of an accurate tachometer
(see Specification for r/min setting).
If carburettor adjustment is performed without a tachometer, only the basic setting adjustment
is recommended.
Before adjusting carburettor, clean or replace air filter, start engine and run several minutes to
bring it to operating temperature.
Idle speed adjustment
Turn idle speed adjuster clockwise until cutting attachment begins to turn, then turn screw out
anticlockwise until cutting attachment stops turning.
Turn screw anticlockwise an additional 1/4 turn.
Basic setting
1. Stop engine and turn both low (L) and high (H) speed mixture adjusters in, clockwise until
they stop and are lightly seated.
2. Turn low speed mixture adjuster (L) out, anticlockwise 1 and 1/2 turn.
Turn high speed mixture adjuster (H) out anticlockwise 1 turn.
Fine tuning
(Requires accurate tachometer)
1. Start engine and allow to run at high idle until warm.
2. Adjust idle speed if necessary (2500 to 3000 r/min).
3. Always begin fine tuning with low speed mixture adjuster (L).
4. Slowly turn (L) adjuster clockwise, try to reach maximum idle speed.
5. Turn (L) adjuster anticlockwise 1/4 to 3/8 turn.
6. Turn idle speed adjuster clockwise until cutting attachment begins to turn.
7. Turn idle speed adjuster anticlockwise 3/8 turn or until cutting attachment stops.
High speed adjustment
(When metal blade)
1. While engine running at full throttle, turn (H) adjuster slowly clockwise until engine runs
smoothly under no load.
2. Turn (H) adjuster anticlockwise 1/8 turn to obtain optimum fuel for full power under the
load conditions.
3. After the high speed adjustment has been completed, and should the engine hesitate
during acceleration from idle to full throttle, turn (H) adjuster anticlockwise until smooth
acceleration is obtained.
Make sure that the final engine speed does not exceed 11000 r/min.
WARNING
When carburettor adjustment is completed, cutting attachment should not move at
idle, otherwise serious personal injury may result.
CAUTION
When starting, idle speed adjuster should be adjusted not to rotate the cutting
attachment.
When there is some trouble with the carburettor, contact your dealer.
NOTE
Do not over tighten (L) / (H) adjusters.
Forcing them to tighten will damage the carburettor.
Improper high speed mixture adjustment can result in lean operation and consequent
severe engine damage.
Do not run engine on full throttle longer than 5 to 6 seconds during high speed mixture
adjuster (H) adjustment to avoid damage to engine.
The engine will overheat when the high speed mixture adjuster (H) is adjusted to the lean
condition reducing engine life.
