Holding Tank / Line Odor Only when Flushing

[Cork the Whine]

Hi,

We have a 1997 355 AC and we've picked up an odor in salon momentarily after the forward head is flushed. It seems to get worse the more the holding tank holds. This odor goes away 5 mins or so after appearing. My bilge is clean and dry and I was wondering if the vent may be plugged? I'm having a hard time finding the vent. It's almost like it's venting in the boat.

Any advice would be appreciated!!

Thank in advance.

Br,

John

[mjk1040]

Vent should be outside on the same side of the boat right below the pump out fitting and ahead of the side engine room air vents. Another issue is that we do not flush enough water when we use the head. One should hold down the foot handle and count to at least 5 before letting the foot handle up. You may still have an hose issue, wipe a damp rag over the large white hose and see if the rag has the same smell. What type of tank additive are you using? Happy Camper Cleaner and deodorizer works well and I have just recently tried the packets sold at Wal-Mart in the camper supply section and they seem to work well too, just drop in toilet with water, let dissolve and then flush with a half a bowl of water or better. Good Luck.

[tomschauer]

For you forward tank, you have a vented loop for the toilet and a vent line from the tank. On my boat (1998 355) they are tied together with a "T" and a single vent lines runs to the starboard side of the boat forward of the pump out fittings. The vented loop and T are on the bulkhead in front of the starboard engine. Easiest way to get at it, and its not easy is from under the dinette seat. I was getting some gurgling at the toilet and found some stuff in theses fittings, probably from an overfill sometime.

[Dewmyster]

I was getting a similar odor. I changed out the vent filter and it stopped. I believe the A/C was drawing in the odor from the outside when it flushed somehow?

[mjk1040]

Never found vent filters on our 355, where were they on your boat?

[tomschauer]

My 355 had no filters installed from the factory.

[Cooler]

Is your head using water from your water tank for flushing? Maybe that water is stinky and is the source of that odor. Probably not from the head holding tank if it goes away quickly. er

[g36]

My 97 had no holding tank filter

[mjk1040]

Well that's what I thought, they originally did not exist. I just noticed that a PO had circled the annual changing of these filters in the owners manual, so I assumed they were there. Come to think of it I think I bought new ones and after looking for them and couldn't find them to replace 'I threw the new ones in a storage box. A winter project installing them I guess along with fuel tank vent line check valves too!