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ENGINE – POWER SUPPLY UNIT TROUBLE
CHAPTER 2
CAUSE
1)
The fuel tank
cap’s breather is
obstructed, missing
or defective.
2)
Insufficient fuel flow
to carburettor.
3)
Same as item 2.
4)
Air filter clogged.
5)
Carburettor clogged
by dirt or by residue
of stale fuel.
6)
Badly sealed carbu-
rettor needle.
SYMPTOM
2/1
The engine starts
up and stops after
a short time. It is
left off, start-up is
repeated and trouble
occurs again.
2/2
Engine has difficulty
starting or stops
after short time.
2/3
Same as item 2.
2/4
Engine does not
start, especially
when warm, or has
difficulty in starting
and releases smoke
from exhaust.
2/5
Engine does not
start or gives very
little.
2/6
Engine does not start
because it becomes
flooded, or because
oil contains traces of
petrol (oil level
increases).
REMEDY
1)
If clogged, it will be
suffiicient to clean it.
For other cases,
replace cap.
2)
Clean the tank
and blow air jets
inside the fuel output
coupling.
3)
Eliminate the air
bubble.
4)
Clean or replace the
filter element.
5)
Wash, clean, blow.
Replace carburettor.
6)
Clean seat and
needle. Replace
needle. Replace
carburettor.
DEFECT
1)
Insufficient fuel flow. This problem result in the
engine starting while the tank is late in in
supplying the carburettor float chamber. Once
the fuel in the float chamber is consumed, the
engine stops. By leaving the engine off for a
few minutes, the float chamber is able to fill up
agaiin and the engine will start, but the problem
repeats itself.
2)
There is a fine metal net inside the tank that
functions as a fuel filter. If the tank contains
dirt or stale fuel, a film forms on the net that
does not allow fuel to flow.
3)
The problem could be due to the air bubble
inside the fuel pipe caused by the drawing
between one of the couplings and the pipe, or
by too narrow a bend in the pipe or by a pipe
that is too long.
4)
If the air filter is excessively clogged,
carburetion is enriched too much and the
engine is flooded.
5)
If the jet and the internal carburettor holes
become clogged, the engine will not operate.
In some cases, the internal ducts of the
carburettor body become clogged and
cleaning is uneffective.
6)
If the carburettor’s needle valve does not close
properly, the fuel level increases and fuel spills
out through the manifold into the combustion
chamber, thus flooding the engine. If this
situation continues, it becomes dangerous for
the engine because by drawing petrol through
the rings and the cylinder it ennds up in the oil
cup. Here it mixes with the oil, which loses its
lubricating properties causing the engine to
wear irremediably in a short time.
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