I'll agree with Dennis.
I've found that 10/23/50-50 seems to be the best all-around fuel for my use.
I use it in ALL my 4S as well as all my glow engines.
Brodak fuel for the most part. I've uses it in Fox 19, 29 & 35, Atwood Triumph 51, Various K&B, Johnson, McCoy, Super Tiger (15 up through 60), ETA, Orwick, ENYA, OS, etc.
Never experienced a lube-related issue.
Bob Z.