12
20〜45°
Needle-valve adjustment diagram
◆
This diagram is for reference purposes only.
Actual needle positions may differ from those
shown.
To stop the engine, close the throttle completely to cut off
fuel/air supply.
Note :
•
Practical best(optimum) needle-valve setting
Exhaust note starts to change.
Disconnect battery
leads from glowplug at
about this point.
Clear, high-pitched two-stroke
exhaust note
Maximum rpm
setting("Lean").
STARTING
"Rich" needle-valve
setting when starting
the engine.
The engine may stop if
the battery leads are
disconnected from the
glowplug while the
engine is running rich.
Engine
stops
R
e
vo
lu
ti
o
n
s
s
ta
rt
t
to
d
e
c
re
a
s
e
.
to
d
e
Intermittent, high-pitched
two-stroke note
superimposed
on low "four-stroke"
sound.
Note: Although this is a two-stroke engine it fires like a
four-stroke at these rich needle-valve settings-i.e. ignition
of the fuel charge takes place at every fourth stroke of the
piston instead of at every second stroke.
1
2
3
4
5
6
7
13
MIXTURE CONTR
OL ADJUSTMENT CHAR
T
Start the engine.
Make sure that the throttle is
fully open.
Adjust the neede-valve.
Close the throttle gradually.
Find the idling position.
Fix the idling position.
Open the throttle fully.
Does the engine
regain full power?
Continue running at high speed
for 10 seconds.
Close the throttle.
Run at idling speed for 5 seconds.
Does the engine stop?
Apply full throttle.
Does the engine
regain full power immediately?
OK
Refer to the next section.
Re-set the idling position at
a little higher r.p.m
.
S
e
t
th
e
t
h
ro
tt
le
o
p
e
n
in
g
b
y
m
ea
ns
o
f
th
e
th
ro
tt
le
t
ri
m
o
n
th
e
tra
ns
m
itt
er
s
o
th
at
th
e
lo
w
es
t
pr
ac
tic
al
s
pe
ed
, w
ith
ou
t r
is
k
of
th
e
en
gi
ne
s
to
pp
in
g,
is
o
bt
ai
ne
d.
The position where the lowest
p
o
ss
ib
le
r
.p
.m
.
,w
it
h
s
te
a
d
y
running, is obtained.
20-30˚
open from maximum
r.p.m. setting.
Yes.
No
.
Yes.
Engine stops.
Engine stops.
Disconnect the battery leads at mid speed.
Engine stops.
