When you replace the shaft after replacing the cutlass bearing, it would be a good time to make sure that you're engine is aligned. Once she is in the water, use a feeler gauge within the shaft coupler to make sure the tolerances are even all the way around. If not, crack the bolts on the mounts and carefully calibrate engine position until they are. This may help with vibration, when I bought my boat, replaced the bearing and checked for tolerance, I found my engine was quite aways from being properly aligned.