David,
I have a 24 year old McCulloch Eager Beaver Blower/Vac, Model 400048-06 and this is what
the Manual says:
"Use regular grade unleaded gasoline mixed with McCullouch 40:1 custom 2-cycle engine oil for best
results."
"If 2-cycle lubricant other than McCullouch Custom
Lubricant is to be used, it must be a premium grade
2-cycle oil mixed at a 40:1 ratio."
I also have 2 old McCullouch chain saws that
use a 40-1 ratio.
Bj, October 2008