Echo PB-403 Operator's Manual page 17

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.
Tools required: Screwdriver, tachometer (Echo P/N 99051130017)
Parts required: none.
NOTE
Do not adjust carburetor unless necessary. If you have difficultly,
see your ECHO dealer.
Before Adjustment
Check that:
• Air filter is clean and properly installed.
• Spark arrestor screen is free of carbon.
• Blower pipes are installed.
1. Start engine, run at idle for one minute.
2. Complete warm up by running at full throttle for 5 minutes,
operating choke twice to clear air from carburetor chambers.
3. Check idle speed and reset if necessary. If a tachometer is
available, idle speed screw (A) should be set to the specifications
found on Page 8 "Specifications" of this manual. Turn idle screw
(A) clockwise to increase idle speed; counter clockwise to
decrease idle speed.
4. Use a tachometer to adjust idle speed to specifications found on
page 8.
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GENERAL
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ANUAL