Saving Old Seagulls

I have a Villiers Mark 1 magneto, with the 'nut and bolt' points and the four spoke flywheel.

Thanks to the other Charles I now know where the timing should be set (This one has helpfully omitted the fixed timing feature). But I am having problems with the spark.

When 'whizzed up' with the electric drill the spark is always there; a little weaker than I'd like, but is accompanied by intervals of a very intense bright spark. This bright one you could weld with, and it keeps going for a few revs then disappears.

I've cleaned the points and tried various gaps - I'm aware that these chaps need a smaller gap than later models. I've tried different HT leads, and different plugs with different gaps. The points box is scrupulously clean, and the HT contact on the coil is clean too.

This elusive 'big' spark never goes away completely - I'd love to get the thing set up so it doesn't go away at all.

Any ideas

Charles I'm told by a mutual friend that the points gap on these is 10 thou,
Make sure the coil is dry it could have got damp over the course of years, take the points box to bits & check the earthing contacts on the capicitor.
Your right when these are going good you can weld with the spark.

The other Charles UK

Hi Charles.
You say you have tried different gabs on the spark plug, but not what results the different made . Does a little gap produce a stabil spark? And does a big gap make unstabillity . If that's the case, it's very likely that your coil is defect, and that the spark leaves the coil another way than through the leads and plugs. I have not come as far as ignition on my own BS. so this is just experience in all. I have seen many igni.coil. with defect " skin " and when tested, one could get the spark out on a wrong spot.

Charles
I think that the symptoms you describe may indicate a condenser/capacitor problem,particularly if the spark intensity keeps fluctuating.The following explanation is one taken from an article on two stroke motorcycle engines.
“Many have the idea that the condenser stops the points from burning,
but this is secondary to its main function, which is to drain off electrical energy quickly
from the coil's primary winding. This speeds up the collapse of the magnetic field when
the points open and increases the high voltage spark intensity. Without a condenser,
the electrical energy inducted in the coil's high voltage winding would be too feeble to
produce a sparkâ€

hi again.
If the condenser dos not work, it should be shown on the platins,and from my learning the condenser beside protect the platins, controls the speed of
draining the secundary winding. (slowing it down).
Mercury once had a system where they loaded the condenser, and unloaded it into the coil, for a spark, there was only 12v over the platins.