Whenever I attempt to start any engine that has been sitting for years, I always use the "I-V bottle" system for gas. Putting fresh gas into an old tank is just asking for trouble. A good way to rig up an I-V bottle is to use a plastic gas tank off of an old riding lawn mower. Being plastic, you can tell at a glance how much gas is in it. Add a rubber hose, with a shut-off valve, and hang it to the under side of the hood with a small chain or piece of wire. Let gravity do the work. After you get it running good, then you can tackle the old gas tank, & fuel pump. Solve one problem at a time. Hope this is helpful.