Stupid question of the year - why doesn't my bilge pump, pump?

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PhillM

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I have a Johnson 600 GPH pump like this one:


http://www.go2marine.com/item/199105/ultima-bilge-pump-600-to-1-250-gph-12-volt-32-47258-003.html

Its connected to a switch that has "auto" and "manual". There is about an inch of water in the bilge. Set the switch to "auto" but the pump doesn't seem run. When I press the switch to manual, the pump seems to run but no water leaves the bilge.

I lifted the pump out of its clips and checked for debris, opened the pump up and looked around the impeller and it was clear. I unscrewed the pipe and checked that wasn't blocked at the pump end. Ran out of time and so just manually pumped the bilge clear with the other pump.

I'm going down again tomorrow to take a look. I appreciate this could be my entry for stupid question of the year, but anyone got any suggestions?
 
Sometimes these pumps start to seize up, or the brushes wear out, and they don't spin fast enough to work.
 
I agree with Sandyman. Probably 1 inch is not deep enough.

Anyway once the pump starts sucking air and is closed down the water in the outlet pipe will drain back into the bilge. That's where a small pump running along side the big pump can take over and get rid of almost all water in the bilge. (You probably need to use a rag then.)
 
Thanks guys, I think I will add some water to the bilge and check that the pump runs automatically. If it doesn't, at least I will get some exercise on the manual pump!
 
You might need to shake the pipe up and down to prime the pump, even if there is a non-return valve at its end.

P.S. only if you have water that is deeper. One inch is next to nothing.
 
With only 1" water depth, I wouldn't think its sufficient to prime a centrifugal type pump. If you can hear it spinning, it's likely to be working. Only way to completely dry my bilge is with a sponge.
 
macd said:
Sure it's not wired pos to neg? Many pump motors will run this way, but they won't pump very well.
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It used to work fine. But in those days we shipped quite a lot of water both from below and above. Nowadays we don't get that much in, so I usually sponge it out each week. After the recent storms we had a fair bit more than normal, hence playing with the pump.

I think the guys who suggest that there not enough water are on the money. Time for a bucket and a couple of tests.
 
Mine does this unless it's pumped through regularly - I think the non-return valve must get a bit crusty and it usually takes 10 mins of faffing about removing the hose and putting it back on again to get it pumping properly. Of course the boat could have sunk in that time, which would be disappointing:-/
 
wongaero said:
Mine does this unless it's pumped through regularly - I think the non-return valve must get a bit crusty and it usually takes 10 mins of faffing about removing the hose and putting it back on again to get it pumping properly. Of course the boat could have sunk in that time, which would be disappointing:-/
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Well, before that happens the water level would have reached the pump and there would be no more need to prime it... ;)
 
ok so with a couple of bucketfulls of water in the bilge the pump's creating a bit of pressure but is insufficiently primed or cavitating maybe. I'll see if I can test that without committing the ultimate fail of sinking one's own boat while testing the bilge pump...
 
Do remember that these pumps are also cooled by the water they are pumping out. If you run the pump without enough in the bilge, it will overheat and eventually burn out. Also, how are you sensing that there is water in the bilge? the switch probably won't flip until there's a fair amount and it will never totally clear- as described above.
 
Billjratt said:
Do remember that these pumps are also cooled by the water they are pumping out. If you run the pump without enough in the bilge, it will overheat and eventually burn out. Also, how are you sensing that there is water in the bilge? the switch probably won't flip until there's a fair amount and it will never totally clear- as described above.
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I'm sensing the water level in the bilge by lifting the floor boards. The pump uses a inbuilt sensor. :)

Tomorrow I shall top up the bilge a bit and check the pump. I promise I won't go too far and sink the boat (but in case I'd do it will be e51 Mercury around 10.30 am) bring your own GoPro!
 
We snookered my bilge pump by having the switch at shoulder level when crew was in the quarter berth. Accidentally switched to manual and ran all night. When I checked last weekend the paddle bit at the end of the spindle had departed. New switch in new location sorted, bilge pump on order.
 
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