Working on old motors that need a little help: an '84 6Hp Johnson and an '89 15Hp Evinrude. a. I don't have the original fuel lines for either of them. How do I find out for sure that I'm purchasing the right diameter? I'm assuming 3/8 is about right for both. Is it critical to get that right? b. The fuel in my tank has been sitting there for several months. The first thing I want to do is throw it out and start fresh, to eliminate that variable during troubleshooting. Where/ how can I dispose of it easily, safely, and legally? It is an oil/ gas mix.