Bilge pump self-priming problem

[Kim Chapman]

I was winterizing my Catalina 400 MKII today. After draining at the water tanks the bilge had a foot of water. I turned on the bilge pump and although the pump was spinning it would not prime and hence would not pump water. It's worked fine all year when I needed it. After turning the pump on an off a number of times it finally primed itself and took off. Any ideas of why this is ?Thanks...KimC400 #249Toronto

 

[Big Windy]

Bilge Pump

The bilge pump does not need a true 'prime' like a closed water system does...such as the air conditioner. It's a pump that simply pumps. Could you have had something blocking the line or the pump? As long as the hose is in water and clear and the pump is properly working, it should pump water.

 

[Alchemist]

If your boat is newer,

it could be construction debris in the pump. On my '02 320, I had to remove a lot of debris from the bilge and install a washing machine filter (a cute knitted stainless sock) over the inlet of the bilge pump line to keep the little check valves on the diaphragm pump from plugging open with debris. I had to disassemble the pump at least three times until I got all of the gunk out of the line.Your problem sounds very familiar to what I was observing.SteveAlchemist C-320 #909

 

[Bill N]

sounds like an air lock, time to replace the pump?

had a similiar problem on my Catalina 30 a few years ago which burned-up my battery (pump just ran and ran but never pumped out any water).Some pumps are manufactured with an extra little hole to allow air at/around the impellor to escape. If that hole is clogged, you might be able to just clean it.However, if your pump doesn't have the hole (like my old jabsco pump), it could mean the impellor blades are 'cavitating' due to age/wear, either creating the air or preventing the air from being moved out of the impeller.You might be surprised to know that most bilge pumps only have a 1-year warrantee.My suggestion -- you have just gotten the 'failure' warning -- so I'd replace it, as you don't want it to fail next year when you will need it.FYI, I replaced mine with one of the few 5-year warrantee pumps on the market, in think it was a rule 2000 gph unit with a special shaft/bearing that allowed it to have the 5-year warranty.Hope this helps...