prop question

[lathehand]

I have a 77 merc 150 tower of power on my v 20. Got this combo free late last summer.What a great find.After a little work to got it running I launched her.She did well after some fine tuneing on the water. After a great day came time to pull her out of the water I discovered the tilt and trim wasn't working and even with the bypass valve opened i didn't have the strenght to raise the motor by hand.anyway I broke a tip off the prop.I do have a good spare but the boat must have seen some time in salt water and i can't remove the damaged one .I tried spraying it with pb blaster and gentlely tapping on it but it wount budge.Can anyone give me ideas on how to remove it.BTW I replaced the t&t motor so this wount happen again