Echo HC-2400 - Manual (Page 24)

24
Basic Setting
1. Stop engine and turn both LO (B) and HI (A) needles in, CW until
they stop and are lightly seated.
IMPORTANT
DO NOT over tighten needles. Forcing them to tighten will
damage the carburetor.
2. Turn needles out CCW:
HC-1500 LO (B) 1-1/4 turns; HI (A) 1-1/2 turns
Others (LO) (B) 1-1/4 turns; HI (A) 1-3/8 turns
Fine Tuning
(Requires Accurate Tachometer)
1. Start engine and allow to warm to operating temperature (minimum
2 - 3 minutes) while varying engine speed from idle to full throttle.
2. Always begin fine tuning with LO (B) needle.
a. Lean drop-off - With engine idling, turn LO (B) needle slowly
CW (in) to lean drop-off point. RPM will increase, then
abruptly drop-off. Note this position. (1)
b. Rich drop-off - With engine idling, slowly turn LO (B) needle
CCW (out) to rich drop-off point. RPM will increase then
gradually slow and drop-off. Note this position. (2)
c. Final setting - Set needle at mid point between lean rich drop-
off points. (3)
d. Turn needle 1/8 turn CCW (out) making mixture slightly
richer. (4)
CARBURETOR ADJUSTMENT
Non Emissions Models
Level 2
Tools required: Screwdriver with 2mm blade width, Tachometer (ECHO P/N 99051130017)
Parts Required: None
NOTE
If carburetor has limiter caps follow "Carburetor Adjustment" procedures for Emission models on previous page.
Idle Speed Adjustment
Turn "idle" speed adjustment screw (C) CW (clockwise) until blades begin to move, then turn screw out CCW (counter
clockwise) until blades stop moving. Turn screw out, CCW an additional 1/4 turn.
WARNING DANGER
Blades must not move when unit is idling, otherwise serious personal injury may result.
C
B A