Hmm, seems like there are two schools of though on this one.
Multiple earlier posts in this forum are highlighting the /6's ability to handle at least some percent of old varnish and junk in the gas if its diluted with fresh gas. I know that running junk is bad intuitively, of course, but sounds like there is not a consensus about it...
If I wanted to be safe, whats the easiest way to pump out the gas tank? disconnect supply line to carb and let the motor turn over? siphon gas out of tank?