This engine appears to blow whitish/blueish smoke under load. Without load, it rarely smokes. It also appears to be consuming oil as I need to top off oil with 8-16 oz per mow (2-3 hours). Is this a head gasket issue, something more serious (like rings) or am I missing something?

Issue 2;

Changed the oil tonight and filled according to the manual. On the dip stick it showed overfull. It ran fine without load and smoked severely under load. Will draining oil down to proper level fix this? Or did I screw something up royally?

Thanks in advance...

Unless you have a leak somewhere then you more then likely have a ring issue. That's way too much oil to be using. The only other cause could be if you were cutting on an angle for long periods. Like sideways on steep hilly areas.

Reducing the oil level could fix it.