Yep, your old air-cooled engine will get sick and cough, gag, gasp and puke if you make it drink old gas. I've tried it before and got about the same results you did. And on the JB weld in the gas tank . . . If a Super Beetle tank starts leaking, buy a new tank. I tried every kind of patch out there, including grinding it down to bright shinny metal and soilder a patch on it. Every time, I got it to hold gas, it would spring a new leak, just like 67Bugnut said, the next time I filled it up.
