21
Power Blower
o
Perator's Manual
NOTE
The initial carburetor settings for idle adjust screw, idle, and Hi mix-
ture needles are intended to start and run the engine before nal car-
buretor adjustments are made to conform the unit to meet Emission
Regulations. Actual turns required for engine operation may vary.
3. Start engine and warm it up at (WOT) for 3 minutes.
4. Adjust idle mixture needle (A) (CW) to reach maximum engine
speed just before lean drop off.
5. Set idle speed to 3,500 RPM by turning idle adjust screw (D).
Engine RPM should be stable at 3,500 +/- 20 RPM.
6. Turn idle mixture needle (A) (CCW) to reduce idle speed 300
RPM to set idle speed at 3,000 RPM. The idle speed range is 2,900
to 3,100 RPM.
NOTE
Engine speed must be allowed to stabilize a minimum of 20 sec-
onds after each adjustment of idle mixture needle to assure accurate
tachometer readings.
7. Adjust Hi mixture needle (B) (CW) and obtain maximum (WOT)
engine speed just before lean drop off.
8. Turn Hi mixture needle (B) (CCW) to reduce (WOT) engine speed
50 - 100 RPM. Minimum (WOT) engine speed after adjustment
should be 7,100 RPM.
9. Stop engine.
10. Start engine, and verify engine idle speed ranges from 2,900 to
3,100 RPM, and (WOT) engine speed ranges from 7,100 RPM -
7,300. When nal adjustment is completed, the engine should idle,
accelerate smoothly, and attain (WOT) per above specication.
SERVICE INFORMATION PB-250
8
2-3 Adjusting carburetor
1. Start and warm engine speed at WOT for 1 min-
ute.
2. Adjust Idle mixture needle (A) to reach maxi-
mum idle speed with 2.5 mm blade screwdriver (E).
3. Set idle speed to 3,400 RPM by turning Idle
adjust screw (D). Engine RPM should be stable at
3,400 +/- 20 RPM after Idle adjust screw adjust-
ment.
4. Turn Idle mixture needle (A) CCW to reduce idle
speed 400 RPM to set idle speed at 3,000 RPM.
The idle speed range is 2,900 to 3,100 RPM.
NOTE :
Engine speed must be allowed to stabilize
a minimum of 20 seconds after each adjustment
of L mixture needle to assure accurate tachometer
readings.
5. Adjust Hi speed mixture needle (B) to reach
maximum WOT engine speed using 2.5mm blade
screwdriver (E).
6. Turn Hi speed mixture needle (B) CCW to re-
duce WOT engine speed 10-20 RPM. Minimum
WOT engine speed after adjusting should be over
6,900 RPM.
7. Stop and restart engine, and verify engine idle
speed ranges from 2,700 to 3,300 RPM, and WOT
engine speed ranges from 6,900 to 7,300 RPM.
When final adjustment is completed, the engine
should idle, accelerate smoothly, and attain WOT
per above speci cation.
8. After adjusting carburetor, insert and secure new
plug(s) (F) P005-001270 deep in the needle holes
per the Emission regulation using limiter plug tool
(C).
NOTE :
Engine WOT, and idle speed in eld oper-
ation may vary from nal adjustment speci cations
due to changing ambient conditions, fuel, and en-
gine loads. Safe engine RPM variances should be
within the safe ranges for WOT and Idling speed
as listed in Section 1-2, otherwise the carburetor
should be readjusted.
(C)
(F)
(F)
(C)
(A)
(E)
(E)
(B)
(D)
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