Adjusting Carburetor; General Adjusting Rules; Presetting Idle Adjust Screw, L Mixture Needle And H Mixture Needle - Echo CS-310 Service Manual

CS-310

4-7 Adjusting carburetor

4-7-1 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 :
M345-FC/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 12 or 14 inch bar and chain combination
should be installed on the unit, otherwise serious engine damage will occur due to overspeeding.
B. Set L and H mixture needle counterclockwise to rich side stop. Start and run engine for two minutes
alternating rpm between WOT and idle every 5 seconds. Adjust idle adjust screw to 3,200 +/- 200 rpm.
Adjust H mixture needle to 12,500 +/- 300 rpm with limiter cap. If engine does not run correctly after this
adjustment, proceed to the next step 2-2.
IMPORTANT : After adjusting carburetor according to the steps 2-2 and 2-3, 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

A
B
FUEL SYSTEM
RON+MON
) and properly mixed at 50 : 1 with "ISO L-EGD" or "JASO
2
B
A
Tools Required : Small screwdriver with 2.5 mm
blade, electronic tachometer P/N 990511-30017,
limiter cap removal tool with 2.5 mm left-hand
thread P/N 89801. Parts Required : (2) limiter caps
P/N P003-000010.
1. Turn the L and H mixture needles counterclock-
wise to rich side stop to align limiter cap tab (A)
with locating slot (B), using 2.5 mm blade screw-
driver.
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.
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