I am familar with one of the Problem DA 50's. Althought I have not adjusted the engine myself I did listen to it run. 15 years of work in the Small Engine Industry and adjusting thousands of those engines lead me to think that this particular DA was running ok. The problem is and odd one and I talked to Dave (DA) in toledo about it. He was as perplexed as I was and really didn't have a answer. That's understandable because he hadn't seen the engine. I can tell you that Rings that are not seated can cause fuel draw problems, particullary if the cylinder is on the + size and the rings on the - size. I haven't had the engine apart or off the plane. Both may be needed to find the answer to the question. I have no beef with any Engine Mfg. I would just like to discover the answer to this problem.. Regards BobH.