Service manual
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1,
Safety valve
body
4.
Oil
filter
base
2.
SafetY valve spring
5.
Safety valve
3.
"0"
ring
Fig.
12.
Safety Valve, Complete
• Replacing engine
oil
(1) Drain and replace the engine
oil
after the first
35
hrs
of
orrriltion
and
every 75 hrs themafter.
(2) The t,il
is
easier
to
change
il
the engine
is
warm.
(3) Do
not
mix
different
brands
01
oil.
If
a
different
brand
of
oil must be used.
drain
the oil and replace
with
all one
bl and. Also.
do
not
mi x oils
of
different
viscosities.
Combustion System
• Combustion chamber
The engine utilizes a swirl
type
pm-combustion chamber
See
(Fiq. 13). Fuel and air
are
mixed in this
chamber
resulting
in
more efficient combustion. A glow-plug
is
employed to preheat the fuel
for
easy
starts
down
to
5° F
(-15°C).
(.5)
1.
Nozzle
holder
4.
Cylinder head
2.
Nozzle piece packing
5.
Combustion chamber
3.
Glowplug
Fig. 13. Combustion Chamber
(7)
• Valve
Combustion
air.
of
course.
is
brought
in
through the
intake
valve when the descending piston creates a partial vacuum
in
the
cylinder.
Valve stem
seals
should be replaced whenever they are
re-
moved.
If
the stem
seal
are replaced. coat the stem liberally
with
oil
before inserting in the valve guide
to
prevent burning
the
valve stem seal.
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(1)-
__
_
1.
Valve cap
5.
Valve stem seal
2.
Valve spring retainer
6.
Valve guide
3.
Valve spring
collet
7.
Valve
4.
Valve spring
Fig.
14.
Structure
of
Valves
The dimensions
of
the replacement valves and valve guides are
shown
in
Fig 15. When new villve guides are installed. the
bores
should be reamed
to
0.316
to
0.315
in. (S.030
to
S.015mm) after installation. The valve head must
be
recessed
0.043
to
0.055
in.
(11
to
l.4mm)
from
thefaceofthecylin-
der head
to
prevent
it
from
hitting
the
top
of
the piston.
A:
ff
0.316-0.317in.
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0.313-0.314in.
7.960-
7.975mm)
Finished
ID
of
guide I
Uf
nr
. installed in
cylinder.
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(B.015-B.030mm)
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1.059 - 1.067in. 1.295
-1.303in.
(26.9"::V.Tmiii)
132.9
':::"33.1mmJ
Fig.
15.
Standard Dimensions
of
Valves,
Valve Guides,
Valve Gap
0.043-0.055in.
(1.1-1.4mm)
Fig.
16,
Sinking
of
Valve
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