How to remove a recoil starter.

I have a Toro power clear model 38583. I want to replace the recoil starter. There are 4 bolts holding the recoil starter on. The nuts are visible, But when I tried to loosen them, The whole bolt turns. I don't see a way to access the bolt head to hold it while I remove the nut. I would also like to know how to remove the fuel tank from this model. Thank you.