Im hoping so, just seemed a really excessive amount, around a quart or so has drained out. Plugs also had black gunk on them not the typical wet oil .Most likely unburnt oil/gas residue. Not all of the oil which is mixed with the gas gets burned and that is what you are seeing.
Not sure how to do all those tests. I might have to take to a pro shop, if not something basic.A quart ??----Check thermostat on this motor .----Check fuel pump diaphragm.----Inspect float valve in carburetor.-----And pressure test the gearcase.