New to me go kart - fuel tank/engine question

[juvius]

I bought a Path Winder two seater go kart for my kids today. The first one I bought was just too much for them (i'll get it fixed for me and my older son). I paid $175 so I figured I couldn't go wrong. he started it for me and it ran, not real good, but it ran. It has the B&S funpower - model: 136212 type: 0016 01.

The PO must have never oiled the clutch because the copper (brass?) bushing was wore out making the clutch useless. They had way too much oil in the engine. when i opened the fill cap, the amount of oil that came out was already probably more oil than it should have had. once that stopped, i opened the drain plug and got the rest out.

now here is the problem/question: First, the fuel tank is attached to the carb on this model. The guy said that his son, for some reason, started removing the foam from inside the tank. He said he cleaned it out several time and the fuel filter still gets clogged. I took a good look inside and it looks very clean. I see no foreign material at all.
Do i need to replace the tank? or.. do I need to keep cleaning it out? or.. should i find a different style carb and an external fuel tank to fit it? if so.. what would you suggest?

any input will be greatly appreciated...

all my pics so far are on photobucket here:
http://s629.photobucket.com/albums/u...ehale/gokart2/