Yes and no. Two-strokes will foul plugs quicker than a four-stroke but they shouldn't foul if the engine's right. If it's too rich at any speed whether by adjustments, jets, or filter restriction, or even if the points are misadjusted so your spark is weak, you can foul plugs pretty quick. Sorry to be so vague, but it's hard to guess without a hand on it.
Good luck!
Stuck in the seventies- not in the swamp.
(6) Attex, a Hustler, a Super Swamp Fox, (2) Tricarts, (3) Tri-sports, a Sno-co trike, 3 Dunecycles, and a Starcraft! ...so far