Carburetor Adjustment; High Altitude Operation - Echo CS-400 Instruction Manual

Idle adjusting screw
Low speed needle (L)

CARBURETOR ADJUSTMENT

Every unit is run at the factory and the carburetor is set
in compliance with Emission Regulations. In addition, the
carburetor is equipped with "H" (High Speed) and "L"
(Low Speed) needle adjustment limiters that prevent set-
tings outside acceptable limits.
Engine Break-In
New engines must be operated a minimum duration of
two tanks of fuel break-in before carburetor adjustments
can be made. During the break-in period your engine
performance will increase and exhaust emissions will
stabilize. Idle speed can be adjusted as required.

High Altitude Operation

This engine has been factory adjusted to maintain sat-
isfactory starting, emission, and durability performance
up to 1,100 feet above sea level (ASL) (96.0 kPa). To
maintain proper engine operation and emission compli-
ance above 1,100 feet ASL the carburetor may need to
be adjusted by an authorized ECHO service dealer.
IMPORTANT
If the engine is adjusted for operation above 1,100
feet ASL, the carburetor must be re-adjusted when
operating the engine below 1,100 feet ASL, other-
wise severe engine damage may result
High speed needle (H)
1. Before adjusting carburetor clean or replace air filter
and muffler "Spark Arrestor Screen".
2. Make sure the bar and chain are properly adjusted.
3. Start engine and run several minutes to bring to
operating temperature. Flash choke twice during
warm-up to clear any air from the fuel system.
4. Stop engine.
Turn "H" speed needle counterclockwise (CCw) to
stop. Turn "L" speed needle midway between full
clockwise (Cw) stop and CCw stop.
5. Idle Speed Adjustment:
• Start engine, turn "Idle" speed adjustment screw
Cw until the saw chain begins to move, then turn
screw out CCw until the saw chain stops mov-
ing. Turn screw out, CCw, an additional 1/4 turn.
WARNING
Cutting attachment must not move when unit is
idling.
6. Accelerate to full throttle for 2 - 3 seconds to clear
any excess fuel in the engine, then return to idle.
Accelerate engine to full throttle to check for smooth
transition from idle to high speed. If engine hesitates
turn "L" needle CCw 1/8 turn and repeat accelera-
tion. Continue adjustment until smooth acceleration
results.
7. Check idle speed and reset if necessary as described
in item 5. If a tachometer is available idle speed
should be set to 2,650 r/min.
CAUTION
when starting, idling adjustment speed should be
adjusted to prevent the saw chain from moving.
Correct idle speed is 2,650 r/min., or 1/4 turn CCw
from the point the chain stops moving.
when you experience trouble with the carburetor,
contact your dealer.
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CS-400