8
SERVICE INFORMATION
HC-331ES
HC-341ES
2-3 Adjusting carburettor
1. Start engine and warm it up alternating r/min
between WOT and idle every 10 seconds for 1
minute.
2. Adjust Idle mixture needle (D) and obtain maxi-
mum idle speed just before lean drop off with 2.5
mm blade small screw driver.
3. Set idle speed to 4,700 r/min by turning Idle
adjust screw (E). Engine speed should be stable
at 4,700 +/- 50 r/min after Idle adjust screw (E) ad-
justment.
4. Turn Idle mixture needle (D) anticlockwise to re-
duce idle speed 1,700 to 2,100 r/min in the range
of 2,600 to 3,000 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. Turn Idle adjust screw (E) clockwise to increase
idle engine speed to range of 2,800 to 3,200 r/min.
6. Adjust Hi speed mixture needle (G) to obtain
maximum WOT engine speed just before lean drop
off using 2.5mm wide blade screw driver at WOT.
7. Turn Hi speed mixture needle anticlockwise to
reduce WOT engine speed 200 +/- 100 r/min at
WOT.
8. Start engine again and make sure engine runs
in the range of 2,700 to 3,300 r/min at Idling and
the range of 10,500 to 11,700 r/min at WOT. Also
make sure cutting device would not move at en-
gine idle speed and suitable acceleration.
9. After adjusting carburettor, insert and secure new
plug(s) (H) P005-001270 deep in the needle holes
per the Emission directive using limiter plug tool (C).
IMPORTANT : The limiter plugs must be in-
stalled Idle and Hi speed mixture needles holes
to comply with Emission Directive.
NOTE :
WOT, and idle engine speed in
fi
eld opera-
tion may vary from
fi
nal adjustment speci
fi
cations
due to changing ambient conditions, fuel, and en-
gine loads. Safe engine speed variances should
be within the WOT and Idle speed ranges listed in
Section 1-1, otherwise the carburettor should be
readjusted.
(C)
(H)
(D)
(G)
(E)
(C)
(H)
