I've been running the same ratio and oil for a few years now, it was only an issue with the new saw set rich and going easy on it breaking it in. When I run them normally bucking up a wood pile they're fine.Any heavy oil ratio requires a good detergent package & sharper tune to ensure complete combustion to prevent oil residue from accumulating . If you have drool or sponge then your tune , oil or quality of fuel is not adequate for your application !
I figure the ported clones can use a little extra oil to help keep em together.