XXX vibe
I agree with NuttLoose turn the prop 180 deg. but remove any weights first.
Also the balancer you are using may be sensing the prop only. You may have to use a unit such as the Microvibe to sense the prop / engine combination. The engine may have an vibration coming in at higher RPMCould be a piton / conrod / Crankshaft etc.
Good luck
DHW