The following three conditions must be satisfied for satisfactory engine start.
2.
An appropriate compression in the cylinder.
3.
Good sparks at the correct time to ignite the mixture.
The engine cannot be started unless these three conditions are met. There are
also
other factors which make
engine start difficult, e.g., a heavy load on the engine when it
is
about
to
start at low speed, and a high back
pressure due
to
a long exhaust pipe, just
to
say a few.
The
most common causes
of
engine troubles are given below:
B
1. The cylinder filled with
a
proper fuel-air mixture.
111-1
STARTING
DIFFICULTIES
11-1-1 FUEL SYSTEM
No
gasoline in the fuel tank; or the fuel cock is closed.
The carburetor
is
not choked enough, particularly when the engine is cold.
Water, dust
or
gum in the gasoline blocks the fuel flow to the carburetor.
Inferior grade gasoline
or
poor
quality gasoline is not vaporized enough to produce the correct fuel-air
mixture.
The carburetor needle valve is held open
by
dirt or gum. This trouble can be detected as the fuel flows
out of the carburetor when the engone is idling. (Overflow)
This trouble may be remedied, depending on cases, by lightly tapping the float chamber with the grip
of
a screwdriver or the like.
If the carburetor overflows, excessive fuel runs into the cylinder when starting the engine, making the
fuel-air mixture too
rich
to burn. If this happens, remove the spark plug,
and
turn the starting pulley a
few turns in order to let the rich fuel-air mixture out
of
the spark pulg hole into the atmosphere. Keep
the carburetor choke open during this operation.
Dry
the spark plug well, screw it into place, and
try
to
start again.
11
-
1-2
COMPRESSION SYSTEM
If
starting difficultes and loss of power are not due to the fuel system or ignition system, the followings must
be checked for possible lack
of
compression.
1) Engine inside
is
completely dried
up
because
of
a long period of non-operation.
2)
Loose or broken spark plug. This causes
a
hissing noise made
by
mixture gas running out
of
cylinder in
3)
Damaged head gasket or loose cylinder head. A similar hissing noise
is
produced during compression
4) Incorrect Tappet Clearance
If the correct compression is not obtained even after remedying the above, disassemble the engine and
check further as follows:
a)
Valve
stuck
open due to carbon
or
gum
on
the valve stem.
b) If the piston rings are stuck on the piston, remove the piston and connecting rod from the engine,
compression stroke during cranking.
stroke.
and clean, remedy or replace the parts.
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