Water Pump Problems

[Aqua Vitae]

I have a problem; my boat's water pump is a demon serving the devil that is my boat and seeks to drain my finances! Aside from exorcism, I need help making a decision on my next move.

The boat's water pump, a Jabsco 36970-1000 Automatic, rated at 2.8 gpm, refuses to stop running. It cycles a couple of rotations evey 3 seconds or so after charging the lines. I have rebuilt it and installed new barbed ports (for the prevention of backflow through the discharge port). I have bought a new high presure switch, complete with modification kit for this 28(?) year old pump, but have not yet installed it as the old one seems to work satisfactorily. I have inspected the lines to check for leaks, finding none. There is no accumulator tank.

Do I change the pressure switch or return it? Do I install an accumulator tank? Do I use the pump for a saltwater deck washing system (currently don't have one) and install a variable speed pump for the water system?

Oh and one more question: does anyone else have experience with these fairly common, though old pumps? Particularly the temperature of the pump motor after running for 20 or 30 seconds. Mine seems to get quite warm (hot to the touch, but able to be held onto for a while).

Ryan

[scallywag]

Wilmington Piper,

Is there a pin leak in your system? It sounds like the pressure is dropping. I know it is hard to detect water leaks, but is there any place in the bilge that is damp?

John

[Aqua Vitae]

Damp?! It's the bilge, I thought it was supposed to be wet! Am I wrong on that? Anyway, the lines from the pump run in the starboard cabinets, along with the wiring, just easier to get to I suppose. I am in the process of replacing all of these lines, but all i have removed have been waterproof, just nasty to look at and frightening to think of as the transports for my potable water.

[Aqua Vitae]

One other thing, is the move from 1/2" to 5/8" inch line right after the pump an issue? As I understand it, it lowers overall pressure, but I'm ok with what it is now (5/8").

[Pblais]

There are seals in the pump to prevent back pressure loss. Personally I never would use a Jabsco or Par pump for anything important. A pressure test would seem called for though. You need to decide if it is a leak or the pump. It has to be one or the other. I'm more a Shurflo pump preference sailor. Changing the pump if you can find a place that will take it back would be the cheap solution. Rebuilding a Jabsco pump seems like a bad idea.

[hellosailor]

An accumulator tank is ALWAYS a good idea. They would be on every boat except, of course, that would make every boat $100-150 more expensive with less room in some cubby where it had been installed, and we all know how that would impact sales.

As Paul says, either you've got a leak or a defective part. Repairing a 28-year old pump might be a waste, that's a long life for a cheap pump. Either way, you've got to check for a leak in the lines, unless you just decide to replace the pump "regardless" and take pot luck on whether that will fix things.

[senormechanico]

As a test, disconnect the output of the pump and install a short piece of hose with a plug in the end of it. Clamp the end right onto the output of the pump and turn on the power. If the pump still cycles, it's the pump, not your plumbing.

Steve B.

[hellosailor]

Steve, don't they sell those "test hose stumps" at West for something like $49.95 in brass or chrome, your choice of color? [VBG]

[Whimsical]

Have seen several systems, remote agricultural uses rather than marine, that did the same thing without the tank.
Without the accumulator tank it only requires an incredibly small loss of water to drop the pressure enough to initiate a start. The accumulator tank maintains the pressure for quite a large loss, depending on the size of the tank.
Mike

[mike d.]

just replaced my old 1979 (rebuilt in 94) jabsco water pump 3600 series with a new 3800 series pump. the old one only quit because when we bought the boat we did,nt know there was an inline mesh particulate filter. the filter was plugged with crud and overworked the pump. found this out when new pump wouln't pump water either. everything on the outbound side is 1/2" seems to work well enough. though not as much pres. in head area as galley where the lines split.

so Paul i have a shurflo vane pump i bought about 22 yrs ago for another boat and never installed. this pump is also for mutiple fixtures. would this pump deliver more pressure than the jabsco? not trying to steal thread just a quick querry

[Pblais]

Pumps usually are rated gallons per minute so the bigger pump will let the kids run the tank dry as fast as possible. Most compaines have 3 sizes but they don't always match up to each other. Sometimes you might want to rethink the pressure. Sure the shower would put out more water but it puts out more water! Old boat had 130 gallons with a small pump and the new boat has only 60 gallons with the medium sized pump. We run out of water a lot faster than we should. Some of the newer multi stage pumps are quieter and that also makes using a lot of water easier. Just consider what the crew will do with more water pressure that is harder for you to hear. Hand pumps really are not a terrible idea<g>.

[scallywag]

I can account for the water in my bilge. A previous owner decided to run the shower drain into the bilge near the bilge pump. What a surprise for me! Otherwise there is no water in the bilge. I keep the deck fittings sealed.

John

[captstu]

Unless you have an accumulator, your pump will cycle. You can build a $0 accumulator by putting a "T" in a low part of the line and running the new hose vertical as far as possible. Use an old shutoff at the top - maybe a gate valve. The air trapped in the hose is enough of an accumulator for most situations. That said, after installing a constant pressure pump, I'd never use anything else (when replacing). Enjoy a warm shower. /Stu

[Aqua Vitae]

Thanks for the help everyone. I will definitely get an accumulator tank and see of that solves the problem. Paul, thanks for the tip on pump size. It makes perfect sense, but I would never have thought of that until the tank was run out once or twice.

Scally,
Does the routing of your shower drain to the bilge provide you with any problems? I have read that the soapy water can cause quite a stink if soap scum is allowed to occur. I ask this because my shower drains to the bilge also, but I have yet to use it and would like to know ahead of time what I am getting into.

Ryan

[hellosailor]

Ryan-
If you want to see what shower water in the blige is like, just wash your hands in a bowl of sudsy water. Throw in a batch of hair from your brush or razor. Put the bowl in the bilge and let it sit for a week.

If you don't like what you come back to...don't let the shower water drain into the bilge. [g]

If the bowl looks and smells good to you, just add a rubber duck & let the bilge bunnies have at it!