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(Non Emissions Models Without Limiter Caps)
Tools Required: Screwdriver, Tachometer (ECHO P/N 90051130017).
1. Before adjusting the carburetor, clean or replace the air lter and
spark arrester screen.
2. Fill pump housing with clean water.
3. Start engine and run for several minutes to reach operating tem-
perature.
Idle Speed Adjustment
Turn "idle" speed adjustment screw (C) CW (clockwise) until engine
speed reaches 3000 RPM. Turn screw out, CCW an additional 1/4 turn.
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 dam-
age the carburetor.
2. Turn LO (B) needle out, CCW 1-1/4 turns. Turn HI (A) needle out
CCW 1-1/4 turns.
Fine Tuning
(Requires Accurate Tachometer)
1. Start engine and allow to warm to operating temperature (minimum
2 - 3 minutes) varying engine speed from idle to full throttle.
2. Always begin ne 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)
3. HI speed adjustment.
Adjust HI (A) needle with tachometer. Refer to Wide Open Throttle
RPM settings listed in "Specications" on page 27.
4. Check idle speed and reset if necessary. If tachometer is available,
idle speed should be set to the specications found on page 27
"Specications" of this manual.
A
B
C