Hey Yar, I am not an advocate of oil additives nor am I any kind of expert but I have become sold on synthetic oils due to years dealing with motorcycle problems and have seen the improved results of switching to synthetics. I also have revived an old engine or two with the help of Marvel mystery oil. When left sitting for many years there is sometimes a need to break the rings free of the cylinder walls. It will do the trick, smokes like a chimney for awhile though.
