Adjusting Carburettor - Echo CS-600 Service Manual

CS-600

4-6-3 Adjusting carburettor

H mixture needle
3. Set idle speed to 3,600 rpm by turning Throttle adjust screw. Engine rpm should be stable at 3,600 +/-
50 rpm after Throttle adjust screw adjustment.
4. Turn L mixture needle anticlockwise reducing idle speed 800 rpm to set idle speed at 2,800 rpm. The
idle speed range is 2,700 - 2,900 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. Before adjustment, WOT engine speed should be 11,500 rpm or less. If rpm is higher, turn H mixture
needle anticlockwise until 11,500 rpm is achieved. To make the fi nal WOT engine speed adjustment, turn
H mixture needle clockwise in 1/8 turn increments with the engine at idle. After each adjustment, acceler-
ate to WOT, and check rpm. The fi nal rpm should fall within 12,100 - 12,500 rpm at WOT.
NOTE: When H mixture needle is turned completely clockwise, the engine will continue to run. If engine
speed at WOT is above 13,300 rpm, adjust H mixture needle anticlockwise and set maximum engine
speed at less than 13,000 rpm.
C
IMPORTANT: The limiter caps must be properly installed on L and H mixture needles to comply
with Emission Regulations.
7. Start engine, and verify engine idle speed ranges from 2,600 to 3,200 rpm, and WOT engine speed
ranges from 12,000 to 13,000 rpm. Make sure chain does not rotate when engine is idling. When fi nal
adjustment is completed, the engine should idle, accelerate smoothly, and attain WOT per above specifi -
cation.
FUEL SYSTEM
Throttle adjust screw
L mixture needle
c
1. Start and warm engine for 1 minute alternating
engine speed between WOT and idle every 5
seconds. Turn H mixture needle anticlockwise
until engine speed drops to approx. 11,500 rpm at
WOT.
NOTE: Do not run engine at high speed without
load longer than 10 seconds, or engine damage
may occur.
2. Adjust L mixture needle using 2.5 mm blade
screwdriver to reach maximum engine rpm just
before lean rpm drop off.
If chain starts to rotate during adjustment,
decrease engine speed by turning throttle adjust
screw anticlockwise untill chain stops and then
readjust L mixture needle.
6. After adjusting carburettor, put new limiter
cap on the other side (c) of limiter cap tool (C) as
shown. Align limiter cap tabs (A) with locating slots
(B) in extended housing of carburettor and press
limiter caps to the bottoms on L and H mixture
needles respectively.
B
31
A B
A