ORIGINAL: Jascat100
ORIGINAL: Jezmo
In most ignitions the shield IS grounded through the plug. Think DA50 and all the clones out there. It seems, in your case, the braid is not making good contact with the metal cap that goes over the plug so you will have to ground it as you have and just make it permanent.
Just for curiosity what make of engine/ignition is it?
The engine is a 26cc J'en from Just Engines in the UK. I made sure the plug cap was pushed on fully. Looking at the cap, the only contact with the plug appears to be at the top of the plug. At no point does the body of the cap touch the hex of the plug.
What is the best way to ground the plug lead? Is it ok to just run a wire from the case of the ignition box to the engine, or fix a wire to the actual plug wire braid & ground that?
From the picture on the JE website. they show a metal Spark plug cap. The lower part of that cap should snap around the hex of the plug. If you don't have a metal cap I would wonder what ignition you have and if it's just a rubber boot I would send it back. If it is a metal cap you can put a hose clamp around the base of the cap right where it covers the hex and tighten until the cap makes contact with the Hex...there also should be braided wire covering the plug wire, from the spark plug to the ignition box, if that's not there I would surely send it back as the picture on the site does not match what you have.
gene