Gee all of that sounds familiar.
If I were a betting man I'd wager you ran the engine both times on really old gas and that the stuck valves are intake valves. There are some who've had luck freeing stuck valves without pulling the head but IMHO it's time well spent to just pull the head so you can do it right. #1 most important tip is DON'T use old gas! That is unless you like messing with stuck valves and the accompanying bent pushrods and/or broken rocker arms.
