Service Manual

Single Stage Snowthrower Service Manual 9 - 15
GAS POWER SHOVEL
4. Cylinder Compression
A. Cranking pressure is 100 psi. Refer to
"Compression Test Procedures" on page 9 -
16.
Checking Fuel Tank Venting
The fuel tank cap vent allows air into the tank as fuel is
consumed. If this vent is blocked with dust or dirt, the
engine will eventually stall.
1. Remove the fuel tank cap and inspect the vent. If
the cap is contaminated with dirt particles, the
vent may need to be replaced (Figure 216).
Figure 216 0406-033
2. The cap can be disassembled by prying up the
insert with a flat screwdriver. Care should be used
to prevent damage to the insert and the valve.
3. Remove the valve, squeeze the valve to close it,
release it, and hold it up to a light. No light should
be visible through the valve. If light can be seen,
the valve should be cleaned or replaced (Figure
217). Serial Nos. 5000001 and up use a vent that
does not require this test.
Figure 217 0406-034
1. Visually inspect the bottom of the fuel tank for dirt
or other contaminants.
2. If dirt, water, or other contaminants are present,
the tank should be flushed with a small amount of
fuel, and refilled with fresh fuel.
CHECKING FOR SPARK
1. Pull off the spark plug cap and remove the spark
plug.
2. Inspect the spark plug for wear, carbon deposits,
and damage. Replace the plug if it is burnt or
fouled. NOTE: Do not sandblast, scrape, or clean
the spark plug electrodes with a wire brush
because grit may eventually fall into the cylinder
and engine damage will likely result.
3. Check the spark plug gap and adjust it if
necessary to .020 - .024 in (.5 - .6mm).
4. Turn the ignition switch to the “ON” position. (If
the ignition wires have been removed from the
switch, ensure that they are not in contact with
each other or grounding against metal.) Install the
spark plug cap onto the spark plug and ground it
to the cylinder and crank the engine. If a hot spark
jumps the spark plug gap, the ignition system is
working satisfactorily.
NOTE: The spark may be difficult to see in daylight or
other brightly illuminated areas. This test will not
ensure that the ignition system is operating at full
potential.
5. If no spark is seen, disconnect the ignition switch
and repeat the spark test. If no spark is seen,
replace the CDI module.
Do not test for spark where gasoline has been
spilled or flammable vapors may exist. A fire
could result.
CAUTION