Use and Care Manual
25
CS-501P
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 high 
speed and low speed needle adjustment limiters 
that prevent settings outside acceptable limits. 
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. Idle Speed Adjustment: 
• Startengine,turn“Idle”speedadjustment
screw clockwise until the saw chain begins 
to turn, then turn screw out counterclockwise 
until the saw chain stops turning. 
Turn screw out, counterclockwise, an 
additional ¼ turn. 
 WARNING
Cutting attachment must not move when unit 
is idling. 
5. 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. 
6. Check idle speed and reset if necessary as 
described in item 4. 
If a tachometer is available idle speed should be 
set to 2700 r/min. 
 CAUTION
When starting, idling adjustment speed 
should be adjusted not to rotate the saw 
chain. 
Correct idle speed is adjusted 2700 r/min. 
Or ¼ turn CCW from the point the chain 
stops moving. 
When you experience trouble with the 
carburetor, contact your dealer.
Idle adjusting screw
High Altitude Operation
This engine has been factory adjusted to maintain 
satisfactory starting, emission, and durability 
performance up to 1100 feet above sea level (ASL) 
(96.0 kPa). 
To maintain proper engine operation and emission 
compliance above 1100 feet ASL the carburetor 
may need to be adjusted by an authorized ECHO 
service dealer. 
IMPORTANT
If the engine is adjusted for operation above 
1100 feet ASL, the carburetor must be 
readjusted when operating the engine below 
1100 feet ASL, otherwise severe engine damage 
may result. 










