As CurtD says, use lots of all castor oil and don't even think about synthetics. The Fox liner is a leaded steel and is softer than most other similar engines used. That's why Fox made their Superfuel. If you want to make your own fuel then shoot for 30% castor.
If you've had the spray bar out then check to see if it has 2 holes. These aren't exactly 180 degrees apart and should be fitted so that when you look down the venturi you can't see either hole (in other words both holes are pointing very slightly down towards the crankshaft).
Make your first couple of runs absolutely slobbering rich...you may even need to keep the plug connected. Don't let it run in a 2 stroke for at least 30 or 40 minutes and even then I'd only allow it to just break out of a 4 stroke. Rich is good for these engines