On Nov 26, 6:40 pm, "Dave Isherwood" wrote:
Good Evening's All - Much appreciate (incremental) remedies.

Comfit is a Carver 520 with 2*400 gal. tanks. There are two vents on the
sides (2 per each) that will vent diesel after filling 10 gal. into 200
gal void.

I just spent 1.5 hours putting 200 gal. into each of two 400 gal. tanks. We
had to put a cloth over the two vents to stop diesel going into the water.

Do you have any suggestions on how I could fix this?

Dave

Been there. Sometimes the vent lines trap some fuel in a low spot,
like a sink trap, which interferes with effective tank venting. It's
not much fun, but if you wipe off the vent fitting and then get a seal
with either your mouth or rubber hose or something and then blow back
down into the vent line you can clear the trapped fuel and the vent
will breath again. If that was the problem, you'll actually sense the
hose being cleared by some back pressure and then a release along with
some gurgling noise.