runs like a vac leak

Well now we are getting somewhere.i think.. I twisted it today and 16 seemed like a good spot it seemed to like it there..20 was too much and the starter was kicking back it still wants to kick back a little at 16...the stink got a little better the poor running is still there the timing adj didnt help it at all,im gonna do a leakdown test thurs [gone fishin ]tomorrow..this time instead of making a tester ill go buy one..Im still thinking leaking valves..tx for the help