A lot of PWC part sites have detail part lists showing exploded views. Maybe go to one of the sites and mke sure you are removing all the bolts needed. I removed/replaced my pump assembly and it was really tight. I had to tap on the housing constantly as I applied pulling force (sort of like pulling an old brake drum) and also if you look on the housings there are small tabs for wedging a flat blade into to "GENTLY" break the joint.
Anyway thats what I ran into.
Also to note..once I got the impellor shaft/housing out, I had to take it to a shop where they chucked the shaft in a lathe and heated up the impellor to break it free as it was stuck big time. (hopefully yours won't be so tight!)
Good Luck