In 16 years of repairing engines, very few few "problems" were the fault of the engine...You would not believe some of the things people do and blame the engine....ANY manufacurer or representative will almost bend over backwards to resolve a real or supposed problem....There are a few notable exceptions, both of them are no longer around.....
One of the most frequent problems involves the supposed "factory" needle valve settings..Whose factory ? Walbro ? Walbro carbs come from Walbro with the needles open somewhere around 1 1/2 turns open..If the company that uses them doesn't run each engine there is no way that setting can be right...Simply learning how to adjust your own carb will go a long way..
I am a VERY small retailer..Every engine is run and set with a prop of the size usually run with that engine...Due to the altitude here (7000 feet) this setting will usually be too lean everywhere else, so the carbs are opened up slightly to compensate..Sometimes it's right, sometimes not...Adjusting a carb is something the user should be able to do himself...
My .02...
I have no idea what the problem with the BME is, and this is in NO WAY a reflection on ANYONE, just a general observation...