ENGINE
ADJUSTMENTS
ENGINE
COMPRESSION
TEST
To
check
the
engine's compression pressure, warm
up
the
engine,
then
shut it down.
1.
Remove
both spark plug caps and both spark plugs.
2.
Install a compression adapter and gauge in a spark
plug
hole.
3.
Close
the
tlu·u
hull valve (seacock).
4.
Crank the engine several times quickly so
~hat
the gauge
pointer reaches it's maximum.
STANDARD
COMPRESSION
PRESSURE AT 500
RPM:
71
psi, (5
.1
kgf/CM ) ,(0.50
MPa)
with decompressor
186
psi, (13.8 kgf/cm ),
(l.35
MPa)
without
decompressor
5.
Test
the
compression pressure on the other cylinder.
If
either cylinder is below the standard
tTy
adding a
small
amount of engine oil tlu·ough the spark plug hole
and
repeat
the
test.
(a)
If
additional oil causes an increase
of
pressl.Jre,
the
piston ring and/or cylinder
nmy
be
worn
or damaged.
(b)
If additional oil does not increase compression
pressure suspect poor valve contact, valve seizure
or
valve
wear.
6.
Reinstall
the
two
plugs, connect the
wires
and open the·
thru
hull
valve (seacock).
IGNITION
TIMING
The
magneto employs the electric ignition advance system
that
advances ignition timing with an increase
of
engine
speed.
While mnning the engine, check the ignition tinting
with
a timing light.
There
are
nine
(9)
markings
(fDC,
ATDC
5° and BTDC 5°,
10°,
15°,
20°,
25°,
30i
0
,
35) on the flywheel cup.
Check
the
timing while observing the position
of
the carved
marking
on
the
starter case.
WATER
PUMP
BELT
To
remove, replace
or
aojust the belt, loosen
the
pivot bolt
and release the adjusting bolt. Slide the water
pump
bracket
to slacken the belt for removal. When replacing
and
adjusting the belt, set
tl1e
belt very tight and tighten
the
bolt
and
nut
The dual water pumps on the
FRESH
WATER
COOLED
.
MODELS
use the saine drive belt and the adjustment is the
Bame.
'... '·,
WATER
PUMP
BRACKET
'V'"
''II-,,.:;....
'/;'~;
==-=M--<
-·-·--=~
I~
@:
NOTE:
The
a.djus~~ient
is
the
same
for
the
FRESH
WATER
COOLED
MODEL
dual
pumps.
BTDC
IGNITION
TIMING
IN
DEGREES
30
·25-1----+~.::;;....
___
,
20
10
5
0
""--"'---1+-,f-_..___..___.____,
I
.1
FLYWHEEL
0 3 4 5 6 x 103
Engine speed rpm
Engines
&
Generators
26
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