FUEL SYSTEM
CS-271T
28
4-7 Adjusting carburetor
4-7-1 General adjusting rules
A. Before adjustment, check the following items.
1. The correct spark plug must be clean and properly gapped.
2. The air filter element must be clean and properly installed.
3. The muffler exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel filter are in good condition and clear of debris.
5. The fuel is fresh ( > 89 octane :
RON+MON
) and properly mixed at 50 : 1 with “ISO L-EGD” or “JASO
M345-FD” 2-stroke oil.
6. The recommended bar and chain must be installed, and properly tensioned.
NOTE :
In order to achieve proper carburetor adjustment, a 10 or 12 inch bar and chain combination
should be installed on the unit, otherwise serious engine damage will occur due to overspeeding.
B. Adjustment with limiter caps on carburetor.
Set L and H mixture needles fully counterclockwise (CCW). Start and run engine for 100 seconds alter-
nating engine speed between WOT and idle every 5 seconds. Adjust idle adjust screw to 3,200 +/- 200
rpm. Adjust H mixture needle to 11,900 +/- 600 rpm by turning H limiter cap. If engine does not run cor-
rectly after this adjustment, proceed to the next step 4-7-2.
IMPORTANT : After adjusting carburetor according to the steps 4-7-2 and 4-7-3, the limiter cap(s)
must be installed on L and H mixture needle(s) to comply with Emission regulation.
4-7-2 Presetting idle adjust screw, L mixture needle and H mixture needle
Tools Required : Small screwdriver with 2.5 mm
blade, electronic tachometer P/N 900303, limiter
cap removal tool with 2.5 mm left-hand thread P/
N 89801. Parts Required : (2) limiter caps P/N
P003000010.
1. Turn the L and H mixture needles CCW to rich
side stop to align limiter cap tab (A) with locating
slot (B), using 2.5 mm blade screwdriver.
NOTE :
If cap tabs (A) misalign with locating slots
(B), the cap cannot be removed and the center
hole threads will strip. If center hole threads strip,
use 3 mm limiter cap removal tool P/N 89802 to
remove the limiter cap.
2
B
A
B
A
