This is a service we provide to prolong the life of your engine after swamping, sinking etc.  These are not Honda's and are very particular about tolerances and trash in the engine.  You can flush as many times as you want but you will never get all the trash and debris that is caked on the oil pickup screen.  The oil pickup screen is held in with a plate that can only be accessed by taking the engine apart.  What happens is the screen gets clogged and slowly starves the rod bearings for oil.  Then over time it will get harder and harder to start the engine especially when hot until one day it wont start anymore OR it throws a rod through the block.  Most of the time before this even happens it destroys the thrust surfaces and oil valleys on both case halves and then your cases are junk.  It's your machine so flush at your own risk.  These are just the facts of disaster you're flirting with..