Echo CS-303T Operator's Manual page 47

CS-303T
High Altitude Operation
This engine has been factory adjusted to maintain satisfactory starting and
durability performance up to 1,100 feet above sea level (ASL) (96.0 kPa). To
maintain proper engine operation above 1,100 feet ASL the carburetor
might need to be adjusted by an authorized service dealer.
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, otherwise severe engine damage can result.
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" High Speed needle counterclockwise (CCW) to
stop. Turn "L" Low Speed needle midway between full clockwise (CW)
stop and CCW stop.
5. Idle Speed Adjustment:
• Start engine, turn Idle Speed Adjustment Screw "T" CW until the saw
chain begins to move, then turn screw out CCW until the saw chain
stops moving. Turn screw out, CCW, an additional 1/4 turn.
When carburetor adjustment is completed, the saw chain
should not move at idle, otherwise serious personal injury can
result.
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 value listed on
specifications page.
When starting, idling adjustment speed should be adjusted to
prevent the saw chain from moving. When you experience
trouble with the carburetor, contact your dealer.
X7503209108
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