1. General Information
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Troubles Diagnosis
A. Engine hard to start or can not be started
1-13
Check and adjustment Fault condition Possible causes
Loosen carburetor drain bolt
to check if there is gasoline
inside the carbureto
Fuel supplied to
carburetor sufficient
1. No fuel in fuel tank
2. Check if the pipes, fuel tank to carburetor
and intake vacuum, are clogged.
3. Float valve clogged
4. Lines in fuel tank evaporation system
clogged
5. Malfunction of fuel pump
6. Loosen or damaged fuel pump vacuum
hose
7. Fuel filter clogged
Remove spark plug, install it
into spark plug cap, and
perform a spark test.
Perform cylinder
compression pressure test.
Good sparks Weak sparks, no spark
at all
Cylinder compression
pressure normal
1. Malfunction of spark plug
2. Spark plug damaged
3. Malfunction of CDI set
4. Malfunction of AC generator
5. Ignition coil is in open or short circuit
6. Ignition coil wire open or short circuit
7. Main switch malfunction
Low compression
pressure or no pressure
Re-start by following the
starting procedures
No ignition
1. Piston ring seized
2. Malfunction of cylinder valves
3. Worn cylinder and piston ring
4. Cylinder gasket leak
5. Sand hole in compression parts
There are some signs of
ignition; but engine
cannot be started
Remove the spark plug again
and check it.
Dry spark plug
1. Fuel level in carburetor too high
2. Malfunction of throttle valve operation
3. Throttle valve opening too wide
1. Malfunction of throttle valve operation
2. Air leaking through intake manifold
3. Incorrect ignition timing
Wet spark plug
No fuel is supplied to
carburetor
Start with choke applied
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