MG Magnette KA Instruction Manual page 116

Magneto.
Beyond strict observance o f the makers' instructions w i t h regard
t o lubrication, the magneto should require very l i t t l e attention.
It
is advisable t o
periodically remove the distributor moulding and thoroughly clean w i t h a soft cloth
moistened w i t h petrol. The contact points are accurately adjusted before leaving
the Works, and provided that t h e correct lubrication instructions are observed,
should n o t require any attention for a long period. Should the points become
foul through any foreign matter getting o n them, they should be removed and
cleaned and o n replacement t h e gap should be set t o t h e gauge supplied w i t h the
magneto spanner.
It
is particularly important t o see that the switch w i r e terminal o n t h e magneto
is at all times tight, as this not only anchors the switch w i r e b u t also t h e link cable
between the low-tension coil and the contact breaker.
The Detection and Remedy of Ignition Faults. If
a failure o f ignition o r
misfiring occurs, unless the cause i s at once apparent t h e owner is strongly recom-
mended t o proceed i n accordance w i t h the following routine which should quickly
enable him t o locate the trouble.
Before proceeding w i t h the examination, make sure that t h e trouble is n o t
due t o defects i n the engine, carburetter, petrol supply, sparking plugs, etc.
Examine the high-tension cables, i.e. cables f r o m the magneto t o t h e plugs.
I f t h e rubber shows signs o f deterioration o r cracking, t h e cable should be renewed.
Remove the distributor moulding and examine t h e contacts ;
if
necessary, clean
them as previously described. T u r n the engine over by hand, and see that the
contacts come together.
Should all appear t o be i n order, carefully check the switch cable f r o m the magneto
t o the magneto switch for evidence o f earthing out.
If
there i s
s t i l l
n o spark t h e
fault w i l l probably be i n the magneto itself and must be investigated by an electrician.
Misfiring and Bad Starting. Examine t h e sparking plugs. I f necessary,
adjust t h e gaps t o the correct setting (about 18 thousandths o f an inch). Sooty
o r oiled plugs may be dismantled and washed o u t w i t h petrol.
The plugs and high-tension cables may be tested by removing the plugs i n t u r n
and allowing them t o rest o n t h e cylinder head and observing whether a spark occurs
at the points when the engine i s turned by hand.
It should, however, be noted
that this i s only a rough test, since it is possible that a spark may not take place when
t h e plug i s under compression.
Lucas Altette Horns (Type HF317).
A l l electric horns, before being
passed o u t o f t h e W o r k s , are adjusted t o give the best performance, and they w i l l
give long periods o f service w i t h o u t any attention ; n o subsequent adjustment
is required.
Poge Ninety-eight