baitwell loss of flow

[johnb]

I have a 1994 19.5' osprey dc that has a flush baitwell water pick-up. There's no screen or anything over the inlet. It's located on the bottom of the hull about 1' towards the bow in front of the hull drain at the swim platform. I have problems with a continuous flow. I'm constantly turning off the pump & turning it back on again to restart the flow. Sometime it works & sometime it doesn't. The pump continues to run, but the flow stops.
I keep the boat docked, in fresh water, for about 5 months straight. I don't know if moss or vegetaion grows in the opening or not. It's unreachable from the outside when it's in the water. I've checked the pump valve & it's fully open. It seems like at the begining of the season it works better. (maybe there's no junk growing in there yet?)
Anybody else have this problem, or have a solution?

[John Jones]

Probably an "air lock".  How is the hose  routed?  Does it go high then come back down to the well?  Some pumps claim to be air lock proof.  I had that problem on a Key West boat from it's first day in the water.  I ended up having to use a positive displacement pump to have reliable water.

[johnb]

The baitwell input is about 2' to 3' above the pump. I can't see if the hose is higher than the well input. What is a positive displacement pump, & where did you find it?

[John Jones]

I do not remember where I got the positive displacement pump but you can do a google search and find them.  I do not have that boat any more.  The positive displacement pumps are expensive and the motor will burn up if flow gets blocked or junk gets in the pump.  What I use now is a SHURflo Bait Sentry pump on both of my boats.  They claim an anti-airlock feature and no motor or seal damage if run dry.  They also have a 3 year warranty which blows the others away as far as warranty.  I have not had any issues with the Bait Sentrys in the 3 years I have had them.

http://www.shurflo.com/pages/Marine/mar ... entry.html

If your pump is mounted horizontally, orient the outlet connection to where it's pointing up.  That helps keep air from getting trapped in the pump housing.

Another thing that works but is a PITA but cheaper than buying pumps.  Put a tee fitting in the discharge line as close as possible to the bait tank and put a valve on the tee.  When the pump stops pumping, opening the valve a little should let the air out and allow the pump to start pumping again.

The best setup is a constant elevation rise in all components from the hull water inlet to the tank discharge fitting with no dips, humps, or loops.  I know that is not easy to do on all boats.

Every time I have shopped for pumps River Marine Supply has had the best prices.

http://www.rivermarinesupply.com/