Echo X750-006 - Manual (Page 20)

20
CARBURETOR ADJUSTMENT
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 Adjustment
High altitude adjustment is not required for proper operation of this
engine.
Level 2.
NOTE
Every unit is run at the factory and the carburetor is set in
compliance with California Emission Regulations.
In addition, the carburetor is equipped with “H” (High Speed
Needle) and “L” (Low Speed Needle) needle adjustment limiters
that prevent settings outside acceptable limits.
1. Before adjusting carburetor clean or replace air filter and
muffler, “Spark Arrestor Screen”.
2. 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.
3. Stop engine. Turn “H” speed needle CCW (Counterclock-
wise) to stop. Turn “L” speed needle midway between full CW
(Clockwise) stop and CCW stop.
4. Idle Speed Adjustment
• Before adjusting blower, install all blower pipes.
Start engine, turn “idle” speed adjustment screw either CW
or CCW until the tip just contacts the throttle plate.
Then turn (2) two additional turns CW for initial setting.
Blower should operate with an even idle at low r/min.
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.
If engine hesitates turn “L” needle CCW 1 /8 turn and repeat
acceleration. Continue adjustment until smooth acceleration
results.
6. Check idle speed and reset if necessary as described in item 4.
High speed needle (H)
Low speed needle (L)
Idle adjustment needle