Is Rust Bullet recommended for use on the inside of small engine gasoline tanks?

No, unfortunately, we do not have a product for the inside of small gas tanks. Rust Bullet was not designed as coating for the inside of a small engine gas tanks. We have not tested for this application and can offer no promise as to what the outcome will be if used as such. When using Rust Bullet Coatings, you must ensure the coating is applied thinly and evenly, and there is no guarantee the inside of the tank is covered evenly throughout. Additionally, the inside of the tank does not receive proper air circulation for the coating to cure properly either. Rust Bullet is not affected by gas itself, and can be used on the exterior.