Head back flow problem

[batkins61]

We have a Beneteau 361 with a Jabsco manual head and a holding tank above and behind the head. This means there is about 3+ ft. of vertical discharge hose between the head and the top of the tank. We always use fresh water to flush. I replaced the joker valve, but encountered back flow into the bowl just a few weeks later. I have since replaced the entire pump mechanism as well as the flapper valve at the base (nearly as cheap as a overhaul kit, w/o the overhaul!), but still have back flow into the bowl.

Since we always use fresh water, do we have to worry about calcium deposits, acid flushes, etc, or is this just the weight of the water in the discharge hose overwhelming the valves? Other than a ball valve, which I would like to avoid, is there anything we can do?

Even if we pump enough times to clear the hose, the backflow water is often blackish (from the rubber hose, I assume), but with no odor to speak of. Is there a discharge hose that won't discolor the water, even if it does back flow some?

Thanks!

[monte]

I smeared a good amount of marine grease on the joker valves when replacing them. Seems to make them seal/last longer

[VoyageOfWanderlust]

Originally Posted by monte

I smeared a good amount of marine grease on the joker valves when replacing them. Seems to make them seal/last longer

Yes, using grease on the joker valves and O-rings seems to make them work better and last longer.

I keep a jar of vaseline on hand just for this purpose.

Walt
s/v Wanderlust
Passport 545

[thinwater]

Use Rairitan (red) joker valves in the Jabsco (drop-in fix). Expect a slight increase in pumping efort, but side-by-side testing sugjests they last considerably longer.

Yes, there is still some build-up, just like you see in urinals. Low flow. Just less than seawater.

No, the water is not blackish from the hose (). Bacteria that have been in an anerobic environment often shift to black.

---

And don't figure a marine head will ever be the same as a home toilet using 10x as much water to a gravity drop. That's just not common sense.

[monte]

One question, we have head with a holding tank we use for 'sitting down' , and the other for standing. We notice the standing head has a calcium type deposit on the outlet pipes where the other doesn't. Is this because we don't flush as much seawater through after?