Sachs SA 280A - Page 60

ENGINE
FAULTS
A number of possible fa ults are listed below, t ogether with likely cau ses.
A.
Engin e re fu s es to sta rt
4.
Locating pin for contact-breake r
a)
Pl ug not sparking, because
arm worn,
5. S park plug or spark pl ug terminal
1. Plug oi led up, da mp, s ho r te d or
or ig ni tion ar m ature n ot in order ;
damaged,
b) Engine four-strokes and does not
2.
Exteri or of plug we t,
3.
lqn i tion lead loose or br oken ,
reach speed, because
4.
Short -ci rcuit button jams, or
1.
Choke closed,
leads from engine are damaged,
2.
Carbur ett or f l oods due to clogged
5. Breaker-contacts oiled up, damp or
or
damaged inl et needle seating,
burnt,
3.
Exhaust du ct c logg ed with carbon ,
6. Ign ition armatu re or co n de nser
4.
Ca rburettor setting incorre ct or jets
damaged.
loose,
0
b)
No fuel reaching engine, because
5. Intake sile ncer soiled.
1.
No fuel in tank,
c) Engine pinks at full speed under
2. Fuel cock closed,
load, because
3. Fuel strainer clogged, 1. Ignition too far advanced,
4.
Fuel line blocked, 2.
Combustion chamber needs
5. Je ts clogged. decarbonizing ,
c)
Fuel mixture not igni table , because
3.
Coo l ing fins soiled,
4. S mall end bushing worn.
1. Carburettor flooded,
2.
Water in carburettor,
d) Engine backfires or spits into
3. Infiltrated air due to loose
carburett or , because
ca
rbu retto r.
1.
Engine not getti ng adeq uate fue l,
d)
Lack of compression, because
2.
Spark plug glows due to inco r rect
1. Piston rings broken,
heat value,
3.
Spark plug short ed, dirty or
2.
Pi s ton and cylinder worn,
vitrified,
3.
V ent cock on crankcas e op en,
4.
Engine getting infi l trated air,
4.
Cylinder head or spark plug loose.
5. W ater in ca r burettor .
B. Engin e l ac ks p ower
e) Engine gets too hot and piston
seizes, because
a)
Due to dirty components, becau
se
1.
En gine badl y decarbonized (piston
1.
I nt ake si lencer soil ed,
crown polished clean),
2.
Ex hau st and transfer ports in
2.
Engine not getting sufficient fuel,
cy lin der clogged with carbon,
3. Carburettor ad justed in correct ly or
:?
3.
Thick carbo n depos it in cy lind er
wrong oil used,
h
ead,
4. Coo ling fins on cyl inder and
4.
Fuel tank gets no air {filler c ap),
cyli nder head soiled,
5.
Spark plug vitrified.
5. Th ere are pre- ign it ions.
b)
Due to lack of compression, b ec ause
f) Engine h
as no idling spee d, because
(see und
er "Lac k of compression,
1. Idling adjus tm e nt screw or idle stop
because").
screw
incorrectly adjusted,
2. Control cab le for butterfly valve
c.
Other en g ine faults
wrongly adjusted,
a)
Engine
runs unevenly, becau se
3.
Ig nit i on arma tur e damaged .
1. I gnition lead loose or damaged ,
g) Fuel consumption
of engine is too
2.
Engine overheats; fue l vapor lock in
high, because
carburettor int errupts fuel s upply , 1. Fu el tank, fuel line or carburettor
3.
Contact - br e ak er poi nts oiled up or
l eaking,
fuse d,
2. Jets to o larg e.
58