Echo HCA-2500 - Manual (Page 7)

SERVICE INFORMATION HCA-2500
7
2 EMISSION ADJUSTMENT GUIDE
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 filter element must be clean and properly installed.
3. The muffler exhaust port must be clear of carbon.
4. The fuel lines, tank vent and fuel filter 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” 2-
stroke oil.
6. The gear case assembly with blade set adjusted clearance properly must be installed for proper engine
loading.
B. Set L and H mixture needles with limiter caps anticlockwise to rich side stop. Start and run engine for 2
minutes alternating engine speed between WOT and idle every 5 seconds. Adjust idle adjust screw to 2800
+/- 300 r/min. Adjust H mixture needle with limiter cap to 10000 +/- 500 r/min. If engine does not run correctly
after this adjustment, proceed to the next step (2-2).
C. After adjusting carburettor according to the steps 2-2 and 2-3, the limiter cap(s) must be installed on L
and/or H mixture needle(s) to comply with Emission Directive.
2-2 Presetting idle adjust screw, L mixture needle and H mixture needle
1. Remove cleaner lid. Turn the L and H mixture
needles anticlockwise to rich side stop and meet
limiter caps tabs (A) with locating slot (B), using 3
mm blade screw driver.
NOTE : If cap tabs (A) misalign with locating slots
(B), there is a chance to strip thread.
2. Screw left hand thread of limiter cap tool 91019
into centre hoIe of limiter cap anticlockwise until tab
of the limiter cap just come out from locating slot.
NOTE : DO NOT COMPLETELY REMOVE
LIMITER CAP FROM CARBURETOR! If the limiter
cap were pulled out completely, there is a chance
that the other mixture needle would turn and limiter
cap tab would misalign with locating slot when
screwing the limiter cap tool into centre hole of the
other limiter cap, and thread is stripped. When the
thread is stripped by limiter cap tool, screw 3 mm
wood screw in the stripped centre hole of the limiter
cap, and pull off the cap.
91019
(Continued)
H
L
(A)
(B)
(B)
(A)