Mystyler - I believe 4 strokes have their place; they are quieter and are just powerful enough for the regular lawn and the average idiot who can only say 'I don't want to have to mix oil'. But with plain bearings, alloy bore, they are not a long term proposition.
Its just new briggs aren't good 4 strokes in my opinion.
Only new engine I would buy is a gxv honda, although these alko loncin 160's look good - cast iron liner and all. Although I hate autochokes
Back to the chuzuki - whats the black pipe on the carby - PCV or carby overflow?