I drilled mine out and screwed in a brass hose barb into the hole with some epoxy. It got me by a few years until I finally replaced it. It never did leak and never was a problem. This may be an option if your tanks are not beginning to crack.

I finally replaced it because of a failure of the top tank cracking across the top on the opposite side.

__________________
AJ

1985 300D (SOLD)