Dismantled the regulator, and it looked fine, could not find anything ste carb.icking in there.Tried to fire it up, and it was running with carb facing upwards. Seems like it got way too much fuel (running 30/20), so I decided to make 1/2 turn on regulator as I was unable to make it run nice with adjusting low/high speed valve. This ended up in leaning it out, and the spinner is now retired as it backfired As conclusion of this, I think the engine is ok, the regulator works as it should( if I understand it right, the regulator controls the amount of fuel to be delivered to the carb. Visually, I saw a great reduction in fuel allowed from the regulator when turned 1/2 turn in, and another turn in made it almost completely shutting of fuel to the carb.), so I guess it's just to find the right spot for the regulator to make it run fine (offcourse I will adjust high and low speed valves to ). Please advice if I'm misunderstadning the function of the regulator, I'm not an expert on these engines but have enjoyed the power of the YS63 for about a year with only minor problems (Regulator).

Thanks a lot for your help !