Hope somebody can help - recently bought what appears to be an all original in not running condition. It had sat for two years after last use. Put in new battery, rebuilt the B&S 16HP carb, changed oil, fresh gas. It started. Adjusted carb. Seemed all good. Shut off. Half hour later it wouldn't start. Plug in left cylinder (from front) was dry. Right side wet. Looking down throat of carb there was some gas laying in bottom of intake manifold. Tried starting fluid anyway but to no avail. Don't know what to do. Any suggestions? Thanks!