Well I've been down having a look....
Mayonnaise isn't as bad as first seemed. For now, I'm going to convince myself it's just a little moisture from lying up. It hasn't completely emulsified the oil, more a little build up on the sight glass and cap. Wiped off the cap and not returned, and from what I can see of the internal components the oil still seems like oil.
Starts up from warm with no appreciable smoke, but once it heats up, maybe 2 or 3 minutes, the smoke gets progressively worse until I'm choked out of the garage. Fuel by the smell of it.
I dug out the weep hole, it was full of crud, but nothing is leaking from there that I can see.