The magneto has been drying out partly in a warm oven for a few days and undone and cleaned all terminals / joints.

I set it up in the lathe to spin it over and and find that there is a small spark if I connect a wire to the junction of the coil and the capacitor, the other end to the body. There is a much tinier spark if I touch a wire onto the small brass stud coming out of the coil (the other end of the wire is making contact with the body). When I put the rotor arm and cap back on touching either of the two HT leads onto the body there is nothing at all. I have cleaned the contacts, cap points and the various connections internally. The HT leads are wire and have continuity. I have removed the caps and just touching the end of the wire to the body but there is nothing at all.

I cleaned the points and set them to 10 thou and that made an enormous difference, there is now a healthy spark but only on one of the leads.

I have 2 of these mags taken off the engines so I used the other distributor cap and they both are giving the same results, strangely the same lead on both is dead (terminal1). I have undone the screw on the terminal of the cap and removed and remade the connection and again there is a good reading for continuity on the meter. But when I spin it in the lathe I get a healthy spark on one lead and absolutely nothing on the other, so I removed the lead again and used the lead that I know is good from the other distributor cap and still there is nothing. Cleaning the terminals with a diamond stick made no difference. The interior of the cap has been wiped out with industrial alcohol.

Terminals 2 and 3 are linked in the moulding so there is continuity there , terminal 1 is isolated from the others and it is this one that I am not getting a spark from. I have remade the connection, I have swapped over the leads. On every change there has been continuity on my meter but no spark!!!!!!!!!!.

What I find really strange is that this applies to both the magnetos that came on these engines.

Head scratching time.

Photo 1

A new day and a quick run-up in the lathe in the hope that the workshop elves had sorted it out for me but there was no difference whatsoever so presumably they are as baffled as I am.

Last night I called someone who has had experience with Stuart Turners but he is as confused as I am, and said he will ask his mag expert and get back to me. He has had a look at the photos and confirmed that these engines are definately not boat engines despite one of them having a water exhaust. From his dating list it appears that the engine that is not seized dates from between Oct 1935 to Nov 1943 and this one is from the beginning of this period.

But, and here I have another mystery , the other 2 engines are clearly marked ending in CY ( one of the numbers is unclear but the CY is clear), as far as he can see there were no machines with that suffix.

Someone else did say they were from generators which I would say was right as they have a speed regulator. But I still don't know how the 2 units (engine and generator) was coupled.

Can anyone help me please?

Does CY signify anything that may indicate what these engines were originally used for?

The P55 M and the P55 CY appear to be the same, is there a difference?

Why would BOTH magnetos have the same problem?

It's not so much that I am dedicated to restoring the engine to it's original, it is more that a/ I am reluctant to spend any money if I don't have to and b/ it is frustrating not understanding why the thing doesn't work.

As I have no interest in exhibiting the engine I am not concerned if I add a coil to it and drill holes in the magneto body so use the points for timing but obviously that assumes it is not the cap or points, etc that is not the problem.

It is intended to add an electric start using a SIBA starter that I think came from a Citroen 2CV and will probably be by a belt drive arrangement but until I sort out the magneto problem the project will be on hold for a while.