I just read the message I posted friday evening. Sheesh! I had previously
been down to the Apple TGIF in the cafiteria. Three glasses of wine & I was
definitly unfit to drive or post. My appologies for the garbled posting {though
part of it is dealing with a new terminal emulator & new keyboard}.
If anyone could not understand the safety alert about the silent blocks,
send me a message and I will send you a more lucid reply.
RE: MGBs running out of petrol,
Having an electrical fuel pump, you can easily tell if the MG is out of fuel
by listening for the pump. When you first turn on the ignition, you should
hear the pump 'pump up to pressure'. If you do not, either electricity is
not getting to your pump or it is kaput. If the pump keeps running you are
either out of petrol or you have an open fuel line. If you hear it pump up &
stop you have fuel and your pump is working. Electrical pumps you can
hear are real easy to diagnose. Of course you listen before starting the
engine.
If there is fuel and the starter moter turns at an acceptable speed, check the
spark by pulling a wire to a plug. Using an insulated pair of pliers, hold the
plug wire near an unpainted metal surface and turn the engine over. You
should see a blue spark. A yellow spark means low voltage. Your battery
could be low, your coil may have a short, you may have a bad electrical con
connection or more likely, your points have slipped and the gap is too
narrow.
If you have no spark, you need to pull the centre wire on the distributer
cap and hold it near a bare metal surface. When you turn the motor over,
you should see a bright blue spark. If you do, you know the problem is with
the distributer cap or rotor. If you do not get a spark, the problem may be
in an electrical connection, a bad coil or the points.
If you still have not found the problem, pull the distributer cap and rotor.
Have someone turn over the engine. The shaft in the distributer should be rot
rotating and the points should be opening and closing. This is a good time to
reset the points.
If you have not found the problem, its time to get out a 12V test light or
voltmeter. Move the engine until the points are open. Leve the ignition
switch in the on position. The primary electricity goes from the ignition
switch to one side of the coil. It goes through the coil, down a wire
from the coil to the distributer, through the points (when they are closed)
to ground.
With the pints open and the ignition on, put the test light on the connection
to the coil that does not go to the distributer. The light should shine
brightly. If it does not disconnect the wire from the coil and test the wire
again. If it still does not light, you are not getting electricity from the
ignition switch. If it does you have a short (most likely your points or
where the wire goes through the distributer wall).
If the lamp lit when you tested one side of the coil, put the light between
the other coil connetion (Has wire that goes to distributer) and a bare
metal connection. The lamp should light. If not, you have an open coil. This
is the edxcuse you have been looking for to get a Lucas Sport coil.
If the lamp lights, place the lamp at the inside distributer connection
of the wire. If the lamp does not light, you may have a broken wire between
the coil & distributer, a bad connector at the end of the wire or a bad
connection to the
connection to the points.
If the lamp lit, place it on the insulated arm of the points (one is insulated
the other is grounded). It should light. Turn the motor a little so the
points are closed. The lamp should not be lit at any of the test points if
the points are closed. If it is, replace the points. If every thing seems
correct ( the lamp was lit when it was supposed to and went off when the
points closed) and you do not have a spark on the secondary wire coming
from the coil when you turn the motor over, you either have an open
secondary wire or a shorted coil.
Place a new wire between the coil and distributer then test for a spark.
If you do not get a spark, it is time for a new Lucas Sport Coil.
RE distributer caps: I have had caps fail with an open circuit at its centre
conductor. The cap looked in good condition but electricity could not
get from the top of the centre to the rotor.
Hopes this helps speed up future troubel shooting
TeriAnn
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