Also, the engine isn't overcooled by being uncowled. In fact it may very well be running warmer than if it were properly baffled
It IS out of tune, with the plug in the condition yours is in. Make the effort, and take the time to tune it properly right off the bat. Pay close attention to it through the first 5 gallons of gas or so, as the engine breaks in it will require further fine tuning. Engines I have seen at the field, running lawn boy, in the old days, were all a mess. The plugs would easily fowl, and as most would repeat here on the forums, the oil does more harm than good, for our two strokes. There are many better oils to choose from.