G
RASS
T
RIMMER
/B
RUSH
C
UTTER
O
PERATOR
'
S
M
ANUAL
33
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 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)
3. HI speed adjustment.
Adjust HI (A) needle with tachometer. Refer to Wide Open
Throttle RPM settings listed in "Specifications" on page 12.
4. Check idle speed and reset if necessary. If tachometer is available,
idle speed should be set to the specifications found on page
12
"Specifications" of this manual.
WARNING
DANGER
When carburetor adjustment is completed, the cutting attachment
should not turn at idle, otherwise serious personal injury may
result.
