Carburetor Adjustment - Echo CS-310 Operator's Manual

CS-310

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 "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 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. Turn Lo and Hi mixture needles clockwise until lightly seated, and then turn both mixture needles (CCW)
for initial setting as follows.
Lo mixture needle : 2 1/2, Hi mixture needle : 2 1/4
Note: If needles are forced during seating, damage to carburetor may occur.
5. Remove cleaner lid and air filter to see that Idle adjust screw contacts the throttle plate. Turn Idle adjust
screw (CCW) and set the screw until the tip just contacts the throttle plate. Then turn Idle adjust screw
7/8 turns (CW). Reinstall air filter, and cleaner lid.
6. Start and warm engine for 1 minute alternating engine speed between (WOT) and idle every 5 seconds.
Turn Hi mixture needle (CCW) until engine speed drops to approx. 12,500 rpm at WOT.
Note: Do not run engine at high speed without load longer than 10 seconds, or engine damage may occur.
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