Jabsco 43990-0066 O-Ring for 37045 Electric Toilet

Here's the thing about marine heads. The part that most often gives up isn't the motor or the macerator assembly. It's a small rubber O-ring. This is that O-ring for the Jabsco 37045 series electric toilet, the square-profile seal that seats at the wearplate inside the pump body. When yours goes brittle and starts to weep, this is the cheap fix that saves you from pulling or replacing the whole unit.

It's Jabsco part number 43990-0066, a genuine Jabsco seal rather than a generic stand-in. If you've run a 37045 for a few seasons, you already know these electric heads are built to go the distance. The rubber inside them isn't. Heat, waste, and thousands of flush cycles harden any O-ring eventually, and once it hardens it quits sealing. That's when you get the slow drip at the base of the pump, or the faint smell that won't quit no matter how often you scrub the bowl.

How do you know it's the O-ring and not something bigger? Usually the tell is where the water shows up. A weep at the joint between the pump and the base. A little puddle that comes back a day after you wipe it dry. A seal that looks flattened or cracked when you finally pull the pump apart. If the motor still runs strong and the macerator still grinds, the seal is the first and cheapest thing to rule out before you spend real money.

Swapping it is a job most owners can handle right at the dock. You're reseating a seal, not rebuilding the pump. Shut off the supply, pull the pump section the way your Jabsco manual walks you through, lift out the tired O-ring, clean the groove, and set the new one in its place. Take your time and keep the sealing surface clean. A fresh square O-ring that sits flat is what stops the weep for good.

Who's it for? Anyone running a Jabsco 37045 series electric head who's tracking down a leak or getting ahead of one with some off-season service. These square O-rings live in the full Jabsco service kits too, so if you're only chasing a single weeping seal, buying the one part you actually need beats paying for a whole kit.

It fits the 37045 series, and the same family of Quiet Flush designer-style heads shares these internal seals, so check your part number against 43990-0066 before you order and you'll know you've got the right one.

Here's our honest take on keeping a spare. O-rings cost next to nothing and weigh nothing, and a marine head always seems to let go on the weekend you're furthest from a chandlery. We'd toss one or two of these in the spares box right next to your impellers and fuses. When the drip starts, you fix it in an afternoon instead of living with it for a month.

One important note on what this is and what it isn't. This listing is the O-ring seal itself, sold as a package of one. It is not the complete macerator pump, it is not the motor, and it is not a full rebuild kit. If your pump bearings are worn or the impeller's chewed up, you'll want the larger service kit instead. But if you've traced your trouble to a leak at the wearplate on a 37045 series head, this seal is very likely all that stands between you and a dry, quiet toilet again.

The 37045 is the 12-volt electric Quiet Flush head you'll find on a lot of cruising sailboats and trawlers, the compact push-button unit with the china bowl. It's a good toilet. Little parts like this are what keep a good toilet in service for a decade or more. Order the seal, keep the boat moving.