Yes Enrico. We got lost in fun and games. Your problem is serious. Let us try to help with suggestions for your problems.
The ignition timing is fixed, factory set on Seagulls. The small screw under the ignition back plate locates in a dimple in the upper crankcase, that’s it. If this screw is in tight and in the dimple, the timing must be set right.
The points gap is adjustable with the small screw at the points. This is best set to 20 thousands of an inch (=0.5mm) Set the spark plug gap to the same, but make sure you have a good spark plug. Buy a new one to be sure.
Poor compression could be a problem, especially if it is hard to start when hot. Sure, there may be cracks in the cylinder or the head. Does it leak compression gasses that you can see? Does it over heat from water in the cylinder? Does it have water flow out the tell tale hole when running?
but let's investigate simpler things first.
Perhaps the hard starting is because you flood it with too much petrol. NO CHOKE when hot. Not even the carbie dripping. Just half throttle and pull.
If the spark is not strong at any time, as you said in your first post, then you may have a bad spark plug, and/or a bad spark lead. Check them both and or replace them and try again. Or else you may have a weak coil which needs a "spin" (see this page
http://www.saving-old-seagulls.co.uk/faq.htm ) for lots of help on weak spark.
Also, see this thread for a similar problem to yours on the same engine
http://www.saving-old-seagulls.co.uk/fo ... .php?t=118
Sometimes new owners (like me) get frustrated with motors we don't understand yet, but persevere and you will get to love your Seagull. Teething problems can just be problems that the old owner did not address with good maintenance (like my motor when I first got it).
Good luck - and tell us some more about what you find with it and ask some more questions for help from better experienced people than me with the Forty Plus. You'll get there!