Cub Cadet CC 4BP 32cc - Manual (Page 13)

Trouble shooting
10
1e. Match the sample from the carburetor to the
other three samples. This will show if the
proper mix is being used or not.
See Figure 3.3.
1f. Before returning to service, put fresh fuel/oil
mix in the fuel tank.
2. Inspect the spark plug:
• What does the spark plug look like?
• A wet fowled plug indicates the engine is running
rich
• A light colored coating on the plug would mean
the engine is running lean.
3. Inspect the air filter:
• What does the air filter look like? Dirt-blocked, oil
soaked, missing, wrong filter?
• Look for signs of dirt ingestion.
• A dirty air filter would restrict air flow.
• A missing air filter means that the engine has
ingested dirt that could damage the piston and
cylinder.
Most gasoline engine diagnosis involves isolating prob-
lems in the four critical factors an engine needs to run
properly:
Ignition- sufficient spark to start combustion in the cylin-
der, occurring at the right time.
Compression- enough pressure in the cylinder to con-
vert combustion into kinetic motion. It also needs suffi-
cient sealing to generate the vacuum needed to draw
in and atomize the next intake charge.
Fuel- correct type and grade of fresh gasoline/oil mix;
in sufficient quantity, atomized (tiny droplets) and in
correct fuel mix/air proportions.
Flow- if all of the above conditions are met, but the flow
of air is constricted on the inlet or exhaust side it will
cause the engine to run poorly or not at all.
4. To isolate the ignition system and compression
from the carburetor system:
4a. Prime the engine through the carburetor
throat using a squirt bottle filed with clean
fresh gasoline.
CAUTION: Never use ether or starter fluid to
prime an engine, sever damage to the engine
may result.
NOTE: In the past WD 40 was used as a starting
fluid. A change in the propellant used by WD 40
has taken away most of it’s starting ability.
4b. Verify that the engine stop switch is in the
engine run (1) position.
4c. Attempt to start the engine.
NOTE: If the engine starts and runs long enough
to burn the prime, the problem is effectively iso-
lated to the fuel system. proceed to the Trouble-
shooting the Fuel System section of this manual.
4d. If the engine fails to burn the prime, check
the compression.
NOTE: If compression is OK, check ignition sys-
tem as described in Chapter 4:Ignition.
Figure 3.3