Had a wheels up landing in my Sabre, mechanical failure, broken prop, gearbox checked out by Wal , all good, borrowed another prop from a mate, Kaspar, had to change the pitch as it was over reving, now have a bad vibration as is throttles back past 4000 revs , only noticed this as I was flying to deni to get some panel work done, could it be caused by a miss match in the pitch of the blades , cruise and idle it is good , got a mercury balance plate fitted.