Engine needs a rebuild?

Assuming blue smoke considing you said it used alot of oil, but could be leaking too. Black smoke would be more indicative of fuel problems. I'd be a little concerened about additives in a can. Mine sat for a long time befor I got it and had a poorly rebuild carb when I got it. I think it thinned out the oil and loosened a bunch of old sludge and did clog the oil filter. Got luckly and didn't do any long term damage.