This is not my info. I don't really have an opinion one way or another. I just thought it was and interesting conversation. One oil is amsoil interceptor used on a snowmobile engine. Another engine was run on polaris blue a cheaper dino 2cycle. One crank is rusty the other isn't. Pics to compare. The link is from snowest, a snowmobile forum. The author is a reputible engine builder. check it out.
Snowest forum
Snowest forum