Engines stall, pumps stop pumping, and lights stop working quite frequently on boats—it’s part of the game. But there’s perhaps no more troublesome piece of equipment aboard than the good old-fashioned marine head. And we say old-fashioned because manual marine heads—in their current form—have been around for at least 60 years.
That being said, troubleshooting and repairing a manual marine head is quite easy, as long as you know which parts to go after when things go wrong. With that in mind we’ve compiled a list of common problems folks encounter with their manual heads and the right way to remedy each situation. You’ll be happily flushing again before you know it.
Head Will Not Wet Flush
If you’ve got the selector on your head switched to “Wet” or “Wet Bowl” but no raw water is coming in to flush the bowl, you’ve likely got a blockage in the raw water inlet hose. First make sure that the raw water seacock for the head is open, and even if it is open, exercise it a few times to make sure that marine growth hasn’t grown over the through-hull or in the seacock itself and then try flushing again.
No joy? You may have a blockage in the inlet hose leading to the head itself. There are a few things you can try. First remove the hose at the head and at the seacock, making sure you close the seacock first. If you’re so inclined, give the hose a blow with your mouth and see if water and air comes out the other end. If wrapping your lips around a dirty hose isn’t your thing, you can use an inflatable dinghy pump or a shop vacuum set up to reverse flow to try and unclog it. If you’re able to free the blockage, reattach the hose and then test the head to see if inlet water flow is restored. If water still isn’t flowing, there may also be a blockage in the short length of (usually white) hose that leads from top of the head’s hand pump to the bowl. Remove that hose, check for blockages, and reattach it before attempting the wetf-lush routine again. If you’re still not able to get water to the bowl you may have an inlet valve/ball, plunger seal, or other internal parts issue. If this is the case, you may want to jump to the “Rebuilding Your Head” section later in this feature.
Head Flushes with Water When Set to Dry Flush
If you’ve got the inlet selector switch set to “Dry” flush but water is coming into the bowl, consider a rebuild, as this problem can almost always be blamed on a faulty “Wet Bowl/Dry Bowl” selector switch or worn flapper/ball valves in the inlet/outlet section of the head.
Before diving into a rebuild, however, you can remove the inlet/outlet section of the head—it’s generally right behind the inlet/outlet selector switch—to see if it’s clogged or seated improperly. Reinstall after inspection and cleaning, and see if this solves the problem. If it doesn’t, scroll down to the “Rebuilding Your Head” section to see about replacing a number of parts that can cause this issue when worn.
Head Will Not Flush Empty
Not being able to flush waste out of your head is probably the most common—and frustrating—problem folks have with their marine heads… and it’s almost always a blockage that’s to blame. We’re not going to lie: This one can be unpleasant to remedy.
First things first, though. Make sure that your Y-valve is set to the proper discharge point (holding tank or overboard, if legal to do so) and that any discharge seacocks are open (again, only if legal, which is rare). If you are still unable to empty the bowl and it’s difficult to push down on the head’s handle, you’ve almost certainly got a blockage. But before you go through the unpleasant task of pulling hoses full of waste off, make sure that the vent to your holding tank isn’t blocked. You can find this fitting coming off your holding tank and leading to a hull fitting that allows air into and out of the tank. Insects love to build air-blocking nests in these fittings. Also check the vent hose to make sure it’s not blocked.
If your Y-valve is working, its handle is in the right position, and your vent hose isn’t blocked, well… you’ve likely got something blocking the discharge hose. You can try a household plunger, but it will unfortunately only work in one direction (pushing it downward only), thanks to a backflow (joker) valve and flapper valve near/in the head’s discharge elbow. Its job is to prevent waste from back flowing into the bowl on the upstroke of the head handle (see the“Waste Comes Back into Bowl While Flushing” section below).
If a plunger does not work, then unfortunately you’ve got to start disassembling discharge hoses, starting at the head and working your way to the holding tank or discharge seacock. Before you get started, grab yourself a five-gallon bucket and some rubber gloves. You’re going to need them. If you’re wearing nice clothes, cover or change them.
After you’ve removed the first section of hose you can try running an untwisted coat hanger through, depending on the length of hose. Electrical “fishing” tape—a coiled length of flat metal wire on a spool, available at hardware stores—can also be used. You can also put one end of the hose in the five-gallon bucket and try to blow out the house with a shop vacuum that’s been reversed to blow, not suction. Try wrapping a rag around it to create a good seal. If you find no resistance to either of these methods, then move along to the next section of the hose, repeating the process until you’ve located and freed the blockage.
If you’re finding yourself unclogging your discharge line more often than you’d like, there are some steps you can take to prevent having to perform this unpleasant task. It’s easy enough to prevent clogs, truth be told. The old adage, “Do not flush anything you haven’t eaten first,” is still the best advice, and it’s something you should say to your guests when you’re giving a safety briefing before shoving off. Feminine products, paper towels, food, dental floss, etc., have no place in a marine head. You may be able to get away with flushing these things at home, but household plumbing is way more forgiving than the small 1-1/2-inch waste hoses on a boat.
Waste Comes Back into Bowl While Flushing
If waste is slow to empty out of the bowl—or comes back into the bowl on every upstroke of the handle—it’s likely that the joker valve on your discharge elbow is faulty. This valve is generally located inside the discharge elbow, a part of the head that’s usually affixed to the bottom end of the hand pump. The part you’re looking for is a cone-shaped piece of rubber, usually pink or black in color. One that’s gone past its useful life is usually deformed and unable to seal.
Another possible culprit is the waste discharge flapper valve, which is usually located at the base of the hand pump assembly. To get to it you’ll need to remove the assembly. One that’s past its useful life is usually warped or torn.
To fix this problem you’ll need first need to locate the part(s), and that means identifying your head and then heading down to your local marine supply shop for a replacement. You can generally find identifying numbers most anywhere on the head. Look for names such as “Jabsco,” Wilcox-Crittenden,” “Raritan,” “Groco,” etc. You can also snap a picture of the head with your smartphone and then bring it into the marine supply shop. A good store clerk will be able to identify the head for you.
That being said, if your joker valve or discharge flapper valve is defective, you may want to consider buying a rebuild kit and restoring the head to its original glory, so to say. Chances are that if the joker valve is worn, then the rest of the internal parts are near the end of their lives, too. Read on to find out what’s involved with rebuilding a head. It’s not as bad as you might think.
Installing a Rebuild Kit
One sure-fire way to get your head back into top-notch operating condition is to source, purchase, and install a rebuild kit. Use some of the aforementioned tips to find the right one for your specific head. Rebuild kits generally contain all sorts of seals, valves, o-rings, and other components located inside the head’s hand pump. They come with a diagram so you know where each part goes.
Our suggestion is to completely remove the head, take it home, and rebuild it in the comfort of your workroom or garage with all necessary tools close at hand. It will much easier to repair at home than in a cramped head compartment, and you’re less likely to lose parts into your bilge. If your head is installed in a way that makes removing it fairly, well, no worries — you can simply remove the hand pump itself; this is where most of the parts are located anyway.
Once you’ve disassembled the pump, replaced the parts, and reinstalled the hand pump onto the head you’ll likely notice a huge increase in performance and a decrease in bothersome leaks and smells.
Strong Odors from Marine Heads
Lots of folks think that a smelly head is just something you have to put up with if you’ve got one aboard, but there are a few things you can do to keep the smell factor at a minimum.
Instead of rinsing the bowl with raw water from the outside of the boat—which has all sorts of microbes floating in it that can amplify odors—consider having three or four milk jugs full of fresh water aboard that you and your guests can use as flush water. Simply set the selector switch to dry bowl and instruct your guests to pour in about two cups of water for liquid waste and four cups for solid.
Uric acid, found in urine, can have a tendency to build up on the walls of hoses and other components, which can cause frustrating odors. To solve this problem, look for a head cleaner with uric-acid eating microbes to add and leave in your head and discharge hoses when your head will go unused for longer periods of time.
Lastly, if possible, always run fresh water through your head and hoses before leaving your boat—even if it’s only for a day or two. This rinsing keeps wastes from sitting in your head components and discharge hoses for long periods of time and goes a long way toward keeping your head compartment odor-free.
Despite their reputation for smelliness and breakdowns, marine heads can be quite reliable if they’re used carefully and maintained on a regular basis. Adopting the right habits for using and caring for them will significantly cut down on hassle and smell problems. And if you do have to service one, rebuilding a marine head is a great off-season project for when your boat is not in use.