Echo CS-420ES - Manual (Page 7)

SERVICE INFORMATION CS-420ES
7
2 CARBURETTOR ADJUSTMENT PROCEDURE
2-1 General adjusting rules
A. Before starting the unit for adjustment, check the following items.
1. The correct spark plug must be clean and properly gapped.
2. The air fi lter element must be clean and properly installed.
3. The muffl er exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel fi lter are in good condition and clear of debris.
5. The fuel is fresh ( > 89 octane : RON ) and properly mixed at 50 : 1 with “ISO L-EGD” or “JASO FC/
FD” 2-stroke oil.
6. The recommended bar and chain must be installed, and properly tensioned.
NOTE : In order to achieve proper carburettor adjustment, 38 or 45 cm bar and chain should be installed
on the unit. Otherwise serious engine damage will occur due to overspeeding.
B. Start and run engine for two minutes alternating between WOT and idle every 5 seconds. Turn L and
H mixture needles full anticlockwise. Adjust idle speed screw to 2,650 +/- 200 r/min. If engine does not
run correctly after this adjustment, proceed to the next step 2-2.
IMPORTANT : After adjusting carburettor according to the steps 2-2 and 2-3, the limiter cap(s)
must be installed in L and H speed mixture needle(s) to comply with Emission Directive.
2-2 Presetting idle adjust screw, L mixture needle and H mixture needle
Tools Required : Small screwdriver with 2.5
mm blade, P/N 897801-33330 electronic ta-
chometer, P/N 91019 limiter cap removal tool.
Parts Required : (2) P/N P003-000010 limiter caps.
1. Turn the L and H mixture needles anticlockwise
to rich side stop to align limiter cap tab (A) with lo-
cating slot (B), using 2.5 mm blade screwdriver.
NOTE : If cap tabs (A) misalign with locating slots
(B), there is possibility of stripping the threads
made by the removal tool when removing the lim-
iter caps.
(continued)
H
L
B
A A
B