mariner 360 waste tank

[Scott892]

I've noticed on my '07 360 mariner that the holding tank never empties. Always a few inches of liquid left in bottom. Any ideas what could be causing this? How do I empty for winter storage? I don't want pee in there for 6 months.

[km1125]

They likely can't fully empty. The line to the deck pumpout isn't ALL the way at the bottom, and once the level gets low enough that air can start leaking in then it stops sucking in the "other stuff".

You can fill with water and get another pumpout so what's left is pretty diluted stuff. You could even pour a little PG antifreeze in there if you're concerned there's too much water left.

[RGrew176]

Where I get my fuel they do a really great job when pumping out. They draw out all the waste matter then pump in about a half tank of clear water and pump it out. They repeat that process a 2nd time and the holding tank is pretty cleaned out. It's $10 for a pump out unless you are buying fuel then it's free.

They do a great job where I buy my fuel.

[bud37]

That particular one , you can't get it all out because the waste pump out line is a few inches off the bottom.

The last pump out of the year you should flush the tank twice real well while they are pumping out.......common they will help....... then when the waste system is winterized the antifreeze will flush to the tank, that will take care of things.......that is what I have done for years.

[Scott892]

Thanks all. Sounds like this is a common issue. Good to know.