Troy-Bilt 8 HP - Manual (Page 56)

Air cooling system
maintenance
To ensure adequate cooling and
correct engine speed, air m ust be
able to circulate through the air
intake screen, past the engine
cover and over the cooling fins.
E ach day before you start the
engine, inspect it for any debris
that could block the air fiow . U se
a sm all brush or a screw driver
w rapped in a rag to rem ove any
trapped debris.
N ever operate the engine w ith
any of the engine shrouds or covers
rem oved. These parts are carefully
designed to direct cooling air over
all points of the engine. R em oving
any of them could cause danger­
ous hot spots to develop that could
lead to engine dam age.
A
WARNING
To help avoid personai injury, stop
the engine, remove the electric
start key, disconnect the spark
plug wire, and let the engine and
muffler cool before inspecting or
servicing the engine.
Ignition system
maintenance
Y our engine is equipped w ith
electronic ignition. It does not have
a condenser or points, and there­
fore you do not have to perform
any regular “tune-up” m aintenance
on this system other than adjusting
or replacing the spark plug.
Spark plug
maintenance
The spark plug (see P hoto 6-58 or
6-59) provides the necessary spark
to ignite the fuel m ixture in the
engine’s com bustion cham ber. It
is essential to proper engine op­
eration to have a plug that is prop­
erly adjusted and in good condition.
R em ove and inspect the plug
after every 50 operating hours or at
the beginning of each year, w hich­
ever com es sooner.
S ee P age 71 in this M anual
for replacem ent spark plug spe­
cifications.
Plug removal and inspection
A
WARNING
To help avoid personal injury, stop
the engine, rem ove the electric
start key, disconnect the spark plug
w ire, and let the engine and m uf­
fler cool before perform ing spark
plug m aintenance.
1. C lean the area around the
spark plug before rem oving it to
prevent dirt or debris from entering
the engine.
2. U se a plug w rench or spark plug
socket to rem ove the spark plug.
3. Inspect the spark plug:
(a) U se a w ire feeler gauge (P hoto
6-60) to check the electrode
,|r
i
SPARK PLUG
6-58: Spark plug on 7 HP Briggs &
Stratton Engine.
t.
i
c-«— SPARK PLUG
6-59: Spark plug on 8 HP Kohler
Engine.
gap. O n the 7 H P B riggs &
S tratton Engine, the gap is
.030": on the 8 H P K ohler
E ngine, the gap is .025".
(b) C heck the porcelain. If cracked,
do not reuse the plug.
(c) C heck the electrodes. If pitted
or burned, do not reuse the
plug. If the electrodes show only
m oderate w ear, clean carefully
by scraping (do not w ire brush
or sand blast). B e sure en­
tire spark plug is clean be­
fore replacing.
(d) A spark plug show ing a light
coating of gray or tan deposits
and slight electrode w ear indi­
cates norm al engine operation.
If the plug is w et w ith oil, or
has heavy black or blistered
w hite deposits, take it to an
authorized engine service
dealer for analysis.
4. R eplace the plug and tighten it
finger tight. Then use a torque
w rench to tighten it securely (see
chart below ). If you don’t have a
torque w rench, tighten the plug
firm ly by hand. Then use your plug
w rench to gently give it an extra V4
turn. D o not overtighten.
6-60: Checking electrode gap.
54