I’ve an issue with my bilge pump
system that’s really baffling me - hope you guys can help.
The problem. I developed a fresh water
leak into the bilge
(which clearly needs addressing, of course), and noticed that the bilge pump
, a Sahara 750, with built-in float-switch, would operate but sometimes not pump out any water
. I stripped it down and all looked OK, but it still occasionally did it, so I assumed the pump was faulty and replaced it with a Whale Supersub Smart 650. However, I’m still getting the same problem with the pump sometimes running but not extracting any water. And it can occasionally run for up to an hour or so like this when it happens, if I'm not down below to notice it!
If I ‘wiggle’ the Whale pump around a bit when this happens it will sometimes start pumping, then turn off when done. Incidentally, the inlet to the pump is submersed when this happens, so it’s not a case of it taking-in air.
. The pipe from the pump is ¾”. I’m not sure of the length of the run as it disappears into the structure and pops-out under the floor of the starboard cockpit
locker, then into the transom area. But, the pump is about in the middle of the boat, so it would be 20’ if it was a straight run, therefore it must be more than that as it meanders a bit and it rises about 3’ as well. If I blow down the pipe, from the pump end, it takes quite a bit of puff before water in the pipe eventually exits (so the pipe must be going downhill at some point, then back up again, hence holding water), but there’s no resistance when the water has eventually been blown out.
When the pump is pumping-out water, the stream from the through-hull on the transom is about 12”, which I think is healthy.
Oh, one other bit of information. The shower sump
system, which is self-contained, is also in the same bilge
area, is about 18” higher than the bilge pump, and also uses a Sahara 750 pump. I’m not sure of the extraction pipe route
, which is initially different to the bilge pump pipe, but I believe it joins the bilge pump pipe with a Y connector about 6” from the through-hull in the transom. I don’t get any problems with this, which is used daily.
Looking through the forum archives
I see that somebody has previously reported a problem with the Smart 650 randomly operating, so it could be coincidence that I replaced a faulty pump with a troublesome pump, but I think my problem may be a bit different.
I obviously need to stop the freshwater leak into the bilge at some point, but it’s my ‘friend’ at the moment as it has highlighted a potentially greater problem.
Sorry this post is so long, but I thought I’d try and give as much information as possible upfront - I know you guys will otherwise be asking lots of questions.
Any thoughts on what could be going-on here would be greatly appreciated as it’s got me baffled…