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

No. Rust Bullet is not affected by gas itself, but was not designed as a small engine tank sealer on the inside of a small engine gasoline tank. We have not tested for this application and can offer no promise as to what the outcome will be if used as such. Rust Bullet can be used on the exterior, but it was not designed for internal use on a small engine gas tank. There is no guarantee the inside of the tank is covered evenly or thoroughly. The inside of the tank does not receive proper air circulation for the coating to cure properly.