You haven't mentioned that once you get it started it runs fine. Sounds like when your filling tank your filling crankcase too. Are you using remote fill line? I have 3 LA's and one thing I notice is they are hard to prime . So I can't imagine a couple of prime flips flooding engine. I have to put my fingure over the muffler exit a long time to prime good. It's cold out now and starting is a little more of a challenge.