Carburetor, Adjustment – Echo CS-301 User Manual

Page 21

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CaRbuRetoR

aDjustment

Engine Break-In

New engines must be operated a minimum duration

of two tanks of fuel break-in before carburetor ad-

justments 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.

BEFORE MAKING ADJUSTMENTS:

• The correct spark plug must be clean and prop-

erly gapped.

• The air filter element must be clean and properly

installed.

• The muffler spark arrestor screen and exhaust

port must be clear of carbon.

• The standard bar and chain combination must be

installed to the power head, and properly ten-

sioned.

LOW ALTITUDE ADJUSTMENT

Engines that have been adjusted to operate at high

altitudes must be readjusted to operate properly at

altitudes below 2000 feet.

1. Start engine and run for several minutes to reach operat-

ing temperature.

2. Stop engine. Remove grommet cover (A) over “H” and “L”

limiter needles.

3. Start engine and turn the high-speed needle rich (CCW)

until the engine runs between 11,500 and 12,000 RPM.

Then turn the low-speed needle rich (CCW) until the en-

gine does not hesitate when accelerated.

DO NOT REMOVE LIMITER CAPS!

4. Idle Speed Adjustment.

• Turn “idle” speed adjustment screw (B) CW until the saw

chain begins to move, then turn the screw CCW until saw

chain stops moving. Turn screw CCW an additional 1/4

turn.

5. Accelerate to full throttle for 2-3 seconds to clear excess

fuel from engine then return to idle. Accelerate to full

throttle to check for smooth transition from idle to full

throttle. If engine stops or stalls after full warm up return

the unit to your authorized ECHO dealer for adjustment.

6. Install grommet cover (A) over “H” and “L” limiter needles.

HIGH ALTITUDE ADJUSTMENT

High altitude adjustment may be required for proper opera-

tion of this engine above 2000 feet.