It is absolutely normal for some oil to come out of the front bearing and be thrown from the drive washer or flywheel. This will leave a stripe under the engine and on the body. That small amount of leakage is needed so that the front bearing gets lubricated. If there was no leakage you'd have a problem. The only problem would be if the leakage was severe enough that lots and lots of raw fuel was being thrown from there. That would be that the fit of the crankcase to the crankshaft is bad. Remember, the front bearing does not provide any kind of seal. The seal is made by the close fit of the crank and the crankcase between the carburetor and front of the engine.