oily plugs

[lil bubba]

Anyone else have or had this problem? I have a 2008 yamaha 70 2 stroke oil injected . motor runs fine . I just get this oil buildup around the plugs. Plugs are clean around the gap and inside. I never see excessive smoke . Maybe its not fully burning the oil so its not smoking, i don't know. Its like automobile engine oil after it turns black. During the winter it seems to be worse , then the inner part of the plug will get dirty and it will miss different cylinders till about half throttle and after its cleared up it will run fine the rest of the day.