Jabsco 18590 series macerator sewage pump issues

[gulfcoast john]

Hi Brats! A messy lesson for those few with a Jabsco 18590 series black water sewage macerator pump... there are some issues to be aware of which I'll post as a new thread to make future searching easier.
This pump is widely used in trailer boats (which usually have a freshwater sewage rinse system) and sailboats (where saltwater use causes smelly heads, crusting on pipes, corrosion within pumps etc). The pump housing is held together by 4 incredibly skinny bronze tapped rods which corrode in the corrosive environs of human waste and water (esp saltwater). It doesn't take much Net searching to find unhappy buyers who don't get a year before it shows The Initial Early Evidence of Impending Failure (namely, to fly apart spewing sewage all over everything in the compartment when turned on). The bronze rods corrode and break. If you have one, it will likely be mounted under the galley sink starboard side and be plumbed to to the gravity blackwater holding tank and only used when the diverter valve is set for overboard discharge when at least 3 miles out to sea. Jabsco recently changed out the bronze rods with acorn nuts to stainless steel rods with hex nuts, although there may be old models in the retail pipeline.
The macerator pump looks like this:
https://www.amazon.com/Jabsco-18590-2092-Marine-Run-Dry-Macerator/dp/B000O8F9BI/ref=sr_1_1?ie=UTF8&qid=1465514204&sr=8-1&keywords=jabsco+macerator+pump+18590-0000
The old-style skinny bronze structural rods look like this:
https://www.amazon.com/Jabsco-Self-Priming-Sealed-Macerator-Service/dp/B0000AY7W8/ref=sr_1_fkmr0_1?ie=UTF8&qid=1465514204&sr=8-1-fkmr0&keywords=jabsco+macerator+pump+18590-0000
The stainless retrofit structural rods look like this:
https://www.amazon.com/Jabsco-Older-18590-Macerator-Pumps/dp/B00UKC9Y5K/ref=sr_1_fkmr0_4?ie=UTF8&qid=1465514204&sr=8-4-fkmr0&keywords=jabsco+macerator+pump+18590-0000
All from Amazon for my conveinience, shop your own fav sites.
BEFORE ever turning on a vintage model not within the 12 month warranty (or even if it is), try turning the acorn nuts with your fingers...if they turn, that bronze rod has broken. I was lucky that only one of the 4 had broken, which allowed a drip leak we could smell but not a sewage slinging festival under the galley sink, where we keep kitchenware etc and you probably do to. I found that boaters more experienced than I advised rebuilding this unit every 1-2 years. For a pump whose job in life is to move sewage, you will very impressed, as I was, at the quality of the gaskets, which are made of very good quality...well, er, ahem...paper. For various reasons including incompatible above -water through hull size I can't replace this pump with a Whale unit. But I'm satisfied with the upgrade and replaced with a new unit (I'll rebuild the old one in the winter as the spare). We also had a minor leak at the diverter valve due to a slightly loose hose clamp when using a Hontoon houseboat pumpout massive pump made to empty 150-gal houseboat tanks. It was absolutely tight to a screwdriver and a Vise grip, but a 5/16 nut driver got another 1.5 turns on it and every other hose clamp down there. Lesson Learned.
I hope any Brats with this unit discovers a broken rod prior to TIEEOIF. It will save you a huge preventable mess.
And get the nut driver.
Happy Boating!
John

[BTDT]

Thanks and will do

[localboy]

Although we don't use ours a lot in The Sound, we have used it in Canada where the regs are...uh...less stringent. Getting an extra one on board has always been on the list. This just made me put it up higher in priority. Thanks for the "heads up" (pun intended).

[Pat Anderson]

Score another point for the Airhead composting toilet!

[Jake]

Question regarding the end of the OP. How tight is too tight for a hose clamp? I didn't know if screwdriver tight is max or okay to go a littler tighter with socket wrench or nut driver? Probably depends on type of hose/connection. How about the typical engine hose connection?

Jake

[localboy]

A nut driver will tighten hose clamps tighter and more easily than a flat head screwdriver. We are not talking about a ratchet which will provide you extra torque. We are referring to a "screwdriver" handle with a nut driver head.

On most installs, you will not be able to over-tighten them; they will brake or the worm will jump out of the slots. However, I have seen some cheap clamps cut into cheap fuel lines due to poor quality controls which created sharp edges on the band. Lousy quality = you get what you pay for. I always double clamp by connections too.

[nimrod]

checked the macerator on my tug.... Yup, one brass stud was broken. Glad I caught it, thanks for the heads up.

jd

[localboy]

Since the cabinet was pretty empty for the Smart Gauge install, no time like the present to repair the macerator, right? Yeah, well getting it out was not as easy as it could be. See here: http://www.c-brats.com/modules.php?set_albumName=album2553&op=modload&name=gallery&file=index&include=view_album.php

Now it's out and apart. No broken brass studs. But, I just ordered a rebuild kit. The paper gaskets were toast and the impeller was in need of replacement. Not the kind of job I wanna do again, but clorox and water does wonders. Iplan to mount it 1" higher this time.

[thataway]

I suspect that the Jabsco macerator pumps are used for economic reasons or space issues.. An other option is the Dometic SeaLand diaphragm pump. These do not seem to have many of the issues, which the Jabsco do, but take up more room. This keeps the pump motor up out of water in the bilge.


Jabsco and Whale also make similar type of pumps, but may have some of the same issues as the inline Jabsco used on the stock boats where the mounting is dependent on the motor body.

[Will-C]

The best part about switching to a diaphragm type waste pump is that they can be run dry without doing any damage. In conventional impellor type pumps the impellor if run dry can be damaged pretty quickly.
D.D.

[BrentB]

porta potty for us

back on topic
Bad design and kudos for sharing and helping others

[rogerbum]

I had Jabsco macerator pumps on my fish boxes and bottom line - they sucked. I was replacing the pumps almost every year and of course they were in a difficult to access area (even after I had some additional access ports installed). I replaced them with Whale Gulper Grouper pumps and never looked back. The Whale pumps have run fine for 2+ years and I hope they will continue to run as well. I certainly would have replaced them each once if they were the Jabsco macerator pumps. They don't pump out as quickly as the old pumps but they do last longer and that's the experience of many on the net.

[cmetzenberg]

Well my Jabsco 18590-2092 made it about three years. This is the second of these sewage pumps i've had to pull. Right now it is tripping the breaker and I have no idea why. All the electric motor shops are closed cause of corona so i guess i have to replace it. I bought some POS off ebay that was supposed to be some cheap made in china replacement for this; cheap is right, it wont even pull a vacuum.
So what should I replace this with? thoughts?

[thataway]

The shaft has a slotted end. There may be a rubber cap over it. If you can get aa screwdriver on the end, and give it a turn, often this will free up a stuck impeller.

I have a good motor, but several of the brass rods had corroded, so it is only the motor and impeller. If you want the motor, it is yours, along with the other parts. (It came off a SeaLand head, but should be the same motor--I bought the whole head assembly for my son at a Hontoon auction. I put a new motor and macerator on the unit I gave to him.)

[cmetzenberg]