Rustoleum will hold up to 15% fuel with sufficient curing time. One or two days is not enough. Wait a week if you can.

You can even mask it and paint a different color of Rustoleum over it if you don't use super tacky tape. Wait a day or two before masking.

If you need to prime it, the Rustoleum Primer that Fills and Builds works great. But it needs a day or two to harden. It is gray. I like iit for when I need some filling and building and the primer doesn't need to be epoxy based.

If you don't have a spray rig, or if you don't want to have to clean a spray gun, the stuff works well.

If you do have a spray rig, either a gun or an airbrush, I can turn you onto some primer and paint that very works well and has no VOC content.