I've got a 1993 Simplicity Regent Lawn Tractor that just conked out on me this past weekend. I had stopped mowing to pick up some branches and when I went to put it back in gear and re-engage the mower blade, it stalled out. There were no loud noises, telltale puffs of smoke, or other indications there was trouble. At several intervals over the next few hours, I tried to restart it and the engine (Briggs and Stratton 12.5HP) would "crank" but not turn over. Each restart, I would hear a very, very faint pop, the engine would "crank", and I would shortly begin to smell the aroma of gasoline as if the machine was flooding. About a year ago, after I had the transaxle replaced, the mechanics told me that the amount of engine vibration they were seeing was not a good sign but if I kept up the maintenance, it might last quite a while. Was this possibly the end of the line for this engine or is this indicative of another fixable problem? If fixable, any hints on how would I troubleshoot this situation to locate the problem? Thanks in advance for any help.