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Perhaps… Is there sideways slop on the upper end of the crankshaft?
These engines have a very strange upper seal/recirc system that can mess up. There is a vacuum passage in the upper seal/bearing area that is supposed to draw off any residual fuel/oil mix that sneaks past the upper bearing and route it down to the intake manifold.
These systems are kind of tricky, and not well thought out, in my opinion. Sorry, I have not reviewed this entire thread again, but has the crankcase been split apart in the past? Someone may have inadvertently installed an oring around the upper bearing. Installing the oring will block off the vacuum port and probably will result in the mag plate getting sprayed with fuel/oil residue. There is also a vacuum port that runs down from this area into the intake manifold. If this passage is plugged, or perhaps the wrong intake gaskets were used, the same issue will result…