I have a 1994 440. I get a mild head smell which I am sure is due to the aging hoses. The dual vacu-flush setup is a bit convoluted and I dread the thought of replacing the hoses in the bilge. Has anyone heard (I am sure I am dreaming) of an easier fix such as a wrap that goes over the existing hose that helps seal them and keeps the smell from permeating ?? Thanks and I due understand this sounds like a Mickey Mouse way to approach the issue !!
No, there is no easy fix. However, follow your vent hose and make sure there is not a sealand vent filter attached inline to it somewhere. That gets clogged and is supposed to be changed every 2 years. It could definately be a source of your smell. If not, take your vent hose off of the tank and blow it out and make sure it is free and clear as a clogged hose will cause smell. If you decide to change your hoses use the sanitation hose and you're going to need a heat gun to really heat up the ends of the hose to get them off and on if they're the white hose.
If you replace the hose, use a repair coupler to connect the new hose to the old and use the old to pull the new into place. Unless it's impossible in which case you will either spend a lot of money or become very familiar with the joys of marine sanitation.
I have lived aboard four different boats in the last 20 years and my best friend during those years has been a product called 'Happy Camper'. You sprinkle some in the head, let it dissolve, and flush it to the holding tank. It deodorizes the head, the lines, and the tank. Cheapest, best, odor relief ever. Available on line, no commercial connection..........