but it could be just plugs, valves and generally the engine, needs a good run. I did manage to get a Power Valve Piston, which does increase fuel input under load but I've only run it so far on the muffs up to 3,000rpm.
Here are some pics of the plugs, not very good but may help.
The whiter bits on the ends of the electrodes could be just the carbon from the Winterising burning off but then it doesn't explain the misfire.
Ed?????