(B)
(A)
(C)
1
7
4
3
2
(D)
(C)
(A)
1
7
4
3
2
2-3 Adjusting carburettor
1. Start and warm engine for 1 minute alternating
engine speed between WOT and idle every 5 sec-
onds. Turn H mixture needle (C) anticlockwise until
engine speed drops to approx. 12,000 r/min at WOT.
NOTE :
Do not run engine at high speed without
load longer than 10 seconds, or engine damage
may occur.
2. Adjust L mixture needle (B) using D-shaped tool
(A) to reach maximum engine speed just before
lean r/min drop off.
3. Set idle speed to 3,600 r/min by turning Idle
adjust screw (D). Engine speed should be stable
at 3,600 +/- 50 r/min after Idle adjust screw
adjustment.
4. Turn L mixture needle (B) anticlockwise reduc-
ing engine idle speed 800 r/min to set idle speed at
2,800 r/min. The idle speed range is 2,700 - 2,900
r/min.
NOTE :
Engine speed must be allowed to stabilize
a minimum of 20 seconds after each adjustment
of L mixture needle to assure accurate tachometer
readings.
5. After adjustment L mixture needle, WOT engine
speed should be 12,000 r/min or less before
adjustment H mixture needle. If engine speed is
higher, turn H mixture needle (C) anticlockwise
until 12,000 r/min is achieved.
Stabilize engine for
45 seconds alternating engine speed between
WOT for 10 seconds and idle for 5 seconds.
To make the
fi
nal WOT engine speed adjustment,
turn the H mixture needle (C) clockwise in 1/8 turn
increments with the engine at idle. After each ad-
justment, accelerate to WOT, and check engine
speed. The final engine speed should fall within
12,800 - 13,000 r/min at WOT.
6. Start engine, and verify engine idle speed ranges from 2,600 to 3,000 r/min, and WOT engine speed
ranges from 12,500 to 13,500 r/min. Make sure the chain does not rotate when engine is idling. When
fi
nal adjustment is completed, the engine should idle, accelerate smoothly, and attain WOT per above
speci
fi
cations.
NOTE :
Engine WOT, and idle engine speed in
fi
eld operation may vary from
fi
nal adjustment speci
fi
ca-
tions due to changing ambient conditions, fuel, and engine loads. Safe engine speed variances should be
within the WOT, Idle engine speed ranges listed in Section 1-2, otherwise the carburettor should be read-
justed.
SERVICE INFORMATION
CS-550
9
