Some of these motors have an inline oil filter. Normally it is a problem with the main oil tank: as already mentioned the screen or leaking caps. Have seen the fitting clog up where the oil line connects to the tank. Put some oil in the fuel until you get this figured out.
The world will not be destroyed by those who do evil, but by those who watch them without doing anything. Remember what He has done and remember that He is not done yet!-- GOD IS GOOD