Excess after run oil always seeps out of front bearings. Second, if you run that engine rich or on high oil content fuel, it will sweat oil from the front bearing and rear case cover. Once you run lower oil fuel or lean it to race tune, that disappears. Now as for your engine, it should run strong at 2 gallons, unless somoething has gone wrong. I haven't had or seen a dud Speed yet so far that I have tuned, but there can be issues with any engine.