Echo PB-255ES User Manual
Page 7
SERVICE INFORMATION
PB-251
PB-255ES
ES-255ES
7
2 CARBURETTOR ADJUSTMENT PROCEDURE
2-1 General adjusting rules
A. Before starting the unit for adjustment, check the following items.
1. The correct spark plug must be clean and properly gapped.
2. The air fi lter element must be clean and properly installed.
3. The muffl er exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel fi lter are in good condition and clear of debris.
5. The fuel is fresh ( > 89 octane :
RON
) and properly mixed at 50 : 1 with “ISO L-EGD” or “JASO FC/
FD” 2 stroke oil.
6. All blower pipes (fan head type) are installed for proper engine loading. ES-255ES should be blower
setting.
B. Start and run engine for 3 minutes alternating rpm between WOT for 50 seconds and idle for 10
seconds. Adjust idle speed screw to 3,000 +/- 100 r/min. If engine does not run correctly after this adjust-
ment, proceed to the next step 2-2.
IMPORTANT : After adjusting carburettor according to the steps 2-2 and 2-3, the limiter plug(s)
must be installed in Idle and hi speed mixture needle to comply with Emission Directive.
2-2 Presetting idle adjust screw, Idle mixture needle and hi speed (H) mixture needle
Tools Required : Small screwdriver with 2.5
mm blade, P/N 897801-33330 electronic ta-
chometer, P/N 91020 limiter plug removal tool.
Parts Required : (2) P/N P005-001270 limiter
plugs.
1. Remove plugs from Idle mixture needle hole (A)
and H mixture needle hole (B) using limiter plug
tool (C) as follows.
(1)Put limiter plug tool (C) on limiter plug in mixture
needle hole.
(2)Screw limiter plug tool anticlockwise 2 turns into
limiter plug pushing the tool against the plug to en-
gage tool threads.
(3)Pull out limiter plug tool with the limiter plug
from mixture needle hole.
(4)Repeat plug removal procedure for the other
mixture needle.
NOTE : If the plug is damaged and left in the hole,
use a needle or pin-shaped tool to remove de-
formed plug pieces.
2. Turn hi speed mixture needle (B) clockwise un-
til lightly seated. And then turn hi speed mixture
needle anticlockwise 7/8 turns. Turn idle mixture
needle (A) clockwise until lightly seated. And then
turn L mixture needle anticlockwise 4 1/8 turns.
3. Turn idle adjust screw (D) clockwise until its
head touches boss (G) as shown Fig 1. Then turn
idle adjust screw (D) anticlockwise 1 5/8 turns.
Fig1
(A)
(D)
(B)
(C)
(1)
(2)
(3)
(A)
(G)
(D)