Echo CS-400 User Manual

25

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.

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.

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 may 

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” 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. 

Idle adjusting screw

Low speed needle (L)

High speed needle (H)

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.