Maintenance/Repairs
Figure 5-5: Spark plug.
SERVICING
THE
SPARK
PLUG
Check the spark plug yearly or
every 100 operating hours.
Replace the spark plug
if
the elec-
trodes are pitted or burned, or
if
the porcelain
is
cracked. See
Figure 5-5.
• Use Champion J-8C, Autolite
356, or equivalent. In Canada,
replace with a resistor spark plug
(Champion RJ-17LM).
To
Check
the
Spark
Plug:
1.
Shut
off
the engine, disconnect
the spark plug wire
from
the
spark plug,
and
make sure that all
movingparts have come to a com-
plete stop.
2. Clean the area around the spark
plug to prevent debris from falling
into the spark plug hole.
3. Remove and inspect the spark
plug.
• Check the electrode gap with a
wire feeler gauge and set gap at
.030",
if
necessary.
•
If
reusing spark plug, clean it by
carefully scraping the electrodes.
Do not wire brush
or
sandblast.
4. Install the spark plug and
tighten securely.
If
using a torque
wrench, tighten to
15
ft./lbs.
PORCELAIN
SERVICING
THE
SAFETY
INTERLOCK
SYSTEM
The safety interlock system pre-
vents the engine from starting un-
less a vacuuming attachment and
the fan cover are installed. The
system also stops the engine if a
vacuuming attachment or the fan
cover is removed while the engine
is running. When a vacuuming at-
tachment or the fan cover is re-
moved, a circuit closes to ground
out the engine ignition system.
Check the function
of
the safety in-
terlock system by performing the
test described on Page 22.
If
the
system
is
not functioning properly,
either the wiring system or the
switch may be at fault.
With the engine shut
off
and the
spark plug wire disconnected from
the spark plug,
inspect the wiring
system by referring to the wiring
diagram
in
the separate Parts
Catalog. Check for bare, broken,
loose, disconnected, or improperly
routed wires.
If
no fault can be
found in the wiring system, it is
likely that the switch itself is faulty.
A new switch and wire assembly
can be installed by following the
wiring diagram in the Parts Catalog.
engine ignition. In the
ON
position,
it opens the circuit allowing the en-
gine
to
be started by the recoil
starter.
If
the system
is
not func-
tioning properly, either the wiring
or the switch may be at fault.
With the engine
shut
off
and
the
spark plug wire disconnectedfrom
the spark plug,
inspect the wiring
system by referring to the wiring
diagram in the Parts Catalog.
Check for bare, broken, loose, dis-
connected, or improperly routed
wires.
If
no fault can be found in
the wiring system, it
is
likely that
the switch itself
is
faulty. A new
switch and wire assembly can be
installed by following the wiring
diagram in the Parts Catalog.
CAUTION
Do
not
tamper with
engine
governor
which
is
factory
set
for proper engine speed.
Overspeeding
engine
above
factory high
speed
setting
can
be
dangerous
and
will
void engine warranty.
Authorized
service shall
be
sought
if a
problem
exists.
The Engine On/Off Switch is con-
nected to the engine ignition sys-
tem by two wires that lead from
the switch wiring harness (refer to
wiring diagram in separate Parts
Catalog).
In the OFF position, the switch
closes a circuit
to
ground out the
SERVICING
THE
ENGINE
ON/OFF
SWITCH
ASSEMBLY
SERVICING
THE
ENGINE
SPARK
ARRESTER
(IF
SO
EQUIPPED)
If
the muffler on your engine is
equipped with a spark arrester
screen assembly, remove the as-
sembly every 50 hours
of
opera-
tion for cleaning and inspection.
Replace the assembly
if
damaged.
CARBURETOR
AND
IGNITION
SYSTEM
INFORMATION
• The carburetor settings have
been factory adjusted and should
be satisfactory for most conditions.
If
you feel that an adjustment is
needed, see an Authorized
Tecumseh Service Outlet. NOTE:
The engine speed
is
rated at 3750
RPM
(+/- 150 RPM). This speed
rating is obtained with the rotor as-
sembly removed from the machine.
Do not exceed this speed rating.
• The engine is equipped with an
electronic ignition system that does
not use points and a condenser. The
only maintenance required
is
to
ser-
vice the spark plug.
If
you feel that
the ignition system
is
not function-
ing properly, see an Authorized
Tecumseh Service Outlet.
.030"
GAP
-~
-t
/
ELECTRODES
37
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