The flapper is maybe a year old. To the touch it's still pliable and should be making the seal just fine. You do have to hold the handle an extra moment for a full flush though, could it be the flapper isn't the right kind? It's one of those mini-toilets. Could it be there isn't enough water pressure holding the flapper down? That might also be the reason you have to hold the handle... Inside the tank there are 2 levels, one line @ S 3.5, and one line @ S 1.0--it fills to the 1.0 mark. I can't find any other markings other than it was made in Chile. The PO's put it in, it's jammed right up next to the tub. Unless you like to soak your feet in the tub during your morning constitutional, it's a real tight spot... I digress.
I'd hate to waste a flapper and have the same problem, so before I do that, do you guys have any thoughts on what else the prob could be?
PS-I've replaced whole assemblies once or twice before, as well as parts, and I've installed one new toilet myself...I'm definately not a pro, but the figure-it-out part of my brain works ok. Having this forum is quite the advantage, thanks for letting me pick your brains