I was wondering if I can add caster oil or some other oil that I can get local in town to boost oil content . The only place in town has just 2 stroke fuel with 16% oil. The brand he sells is Byrons sport fuel or can I use that fuel in 4 stroke with no ill effects? Thanks

Byron mixes by weight so the actual oil content is more like 14% so it would be very wise to top it up with castor.

yes on the castor, the castor you can get in your local drug store will work fine, just stick 4-6 oz in that fuel and your set

Thank you both for the info.