Once it was home I gave it a good clean up regapped the points and spark plug, put some fresh fuel in and gave it a tug..... nothing, in fact I could only just get a jolt from the coil but no discernible spark.
An evenings searching on the web gave me all I needed to know, these engines usually die due to the copper wire in the coil rotting and turning into green copper oxide.and the spark getting weaker and weaker until it no longer fires.
Step 1: Search for a New One
Or I could get a brand new coil that will need to be modified.
Step 2: Rebuild or Remake?
The required part was soon sawn off ready for machining.
Step 3: Iron End Pieces
A brass template the correct shape and size of the end pieces was cut and the holes drilled and tapped in the iron block.
Step 4: Cut the Curves
The final shape was done by hand with a file.
Step 5: Jig
Step 6: The New Coil
Step 7: Final Assembly
End pieces were than sawn apart ready for trial assembly.
Step 8: Fitting and Testing
Time to fit, connect and test it on the motor! I put the flywheel on, spun without any scraping noises, and a spark was seen at the end of the HT lead. I then fully reassembled the engine.
I put a bit of fuel in the tank, tickled the carb and closed the choke.
First pull a couple of fires so off with the choke.
Next pull and it was running! As there is no exhaust fitted I turned it off after a few seconds but I think I can safely say that my efforts have been amply rewarded.