I always run premium in mine, but it's a bit newer and has two key settings (for regular and premium gas). If you can find an owner's manual or service manual, that should have more guidance, but even if regular is ok, I'd still lean towards ethanol-free premium. Battery delete would mean it was originally electric start; that makes it 20-30lbs lighter. The con is you have to pull start, but I find that to be little inconvenience. The headlight may be a stator going bad, but they're not necessarily as bright as car headlights, especially at idle. For the headlight, I'd just pull it out and take it to a parts store. It sounds like it's still good though.