Echo CS-450 Chainsaw Carburetor Adjustment

Carburetor Adjustment For Echo 450 (CS-450) Chainsaw

The Echo 450 chainsaw 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 settings 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 satisfactory starting, emission, and durability
performance up to 1,100 feet above sea level (ASL) (96.0 kPa). To maintain proper engine operation and emission compliance 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 the echo 450 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 “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 may 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 technical data 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.

Air Filter

1. Check before every use.
2. Close choke ( ).
3. Remove air cleaner cover (A) and air filter (B).
4. Lightly brush dust off air filter, or clean with
   compressed air, or replace the air filter.
5. Install air filter and cover.

Spark Plug

• Check periodically.
• The standard spark gap is 0.65 mm (0.026 in.).
• Fastening torque:13 to 17 N•m (115 to 150 in•lbf).

1. Remove air cleaner cover and remove spark plug.
2. Correct the spark gap if it is wider or narrower than the standard gap.

Check Fuel System

• Check before every use.
• After refueling, make sure fuel does not leak from around fuel pipe, fuel grommet or fuel tank cap.
• In case of fuel leakage there is a danger of fire. Stop using the machine immediately and request your dealer to inspect or replace.

Fuel Filter

• Check periodically.
• Do not allow dust to enter fuel tank.
• A clogged filter (A) will cause difficulty in starting engine
or abnormalities in engine performance.

1. Using a wire bent into the shape of a hook, pull filter
   out through gas port, and inspect filter.
2. When the filter is dirty, replace it.
3. When the inside of the fuel tank is dirty, rinse the tank
   out with gasoline to clean it.

Echo 450 Chainsaw

A Echo CS-450 (450) service workshop manual, parts list and operator manual is available from this website.