Why won't prop fit?

[cddetelich]

Motor is a 1990 Johnson 175. Ordered a stainless prop through iboats, when I installed it got "hung up" on lip of lower unit-the little shoulder on the inside edge of the prop rubbed. I returned to Michgan Wheel, they said it was out-of-round, replaced with new Apollo because they said my prop was discontinued. Used a #101 hub kit, thrust washer wouldn't go all the way on shaft. Used the incorect #100 hub I was originally sent, thrust washer fits fine, but when I tighten the nut the prop shoulder gets wedged into lower unit and won't turn. Original aluminum prop works fine. Any ideas?