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1. GENERAL INFORMATION
Troubles Diagnosis
A. Engine hard to start or can not be started
1-14
Check and adjustment Fault condition Probable causes
Loosen carburetor drain bolt to
check if there is gasoline inside
the carburetor
y No fuel in fuel tank
y Check if the pipes, fuel tank to carburetor
and intake vacuum, are clogged.
y Float valve clogged
y Lines in fuel tank evaporation system
clogged
y Malfunction of fuel pump
Fuel supplied tom
carburetor sufficient
No fuel is supplied to
carburetor
y Loosen or damaged fuel pump vacuum
hose
Remove spark plug, install it
into spark plug cap, and perform
a spark test against engine
round.
y Fuel filter clogged
y Malfunction of spark plug
y Spark plug foul
y Malfunction of CDI set
y Malfunction of AC generator
y Ignition coil is in open or short circuit
y Ignition coil leads open or short circuit
y Malfunction of main switch
Check if sparks Weak sparks, no spark at
all
Perform cylinder compression
pressure test.
Cylinder compression
pressure normal
Low compression
pressure or no pressure
y Piston ring seized
y Malfunction of cylinder valves
y Worn cylinder and piston ring
y Cylinder gasket leak
y Sand hole in compression parts
y Malfunction of throttle valve operation
y Air sucked into intake manifold
y Incorrect ignition timing
Re-start by following the starting
procedures
No ignition There are some signs of
ignition; nut engine can
Remove the spark plug again
and check it.
y Fuel level in carburetor too high
Remove carburetor after 30
minutes and connect a hose
onto fuel rich circuit. Then blow
the hose with air
Dry spark plug Wet spark plug
y Malfunction of throttle valve operation
y Throttle valve opening too wide
Blowing in normal Blowing clogged
y Malfunction of automatic by- starter
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