Carburetor Adjustment - Echo CS-400 - 04-09 Instruction Manual

Idle adjusting screw
Low speed needle (L)

CARBURETOR ADJUSTMENT

Engine Break-In
New engines must be operated a minimum duration
of two tanks of fuel break-in before carburetor adjust-
ments can be made. During the break-in period your
engine performance will increase and exhaust emis-
sions will stabilize. Idle speed can be adjusted as
required.
High Altitude Operation
This engine has been factory adjusted to maintain
satisfactory starting, emission, and durability perfor-
mance up to 1,100 feet mean sea level (MSL) (96.0
kPa and below). To maintain proper engine operation
and emission compliance above 1,100 feet MSL 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 MSL, the carburetor must be re-
adjusted when operating the engine below 1,100
feet MSL, otherwise severe engine damage can
result.
CS-400
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 turn, then
turn screw out CCW until the saw chain stops
turning. 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 acceleration. 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 2400 - 2900 r/min.
CAUTION
When starting, idling adjustment speed
should be adjusted not to rotate the saw
chain. Correct idle speed is adjusted 2400 to
2900 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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