Finger in Hole Test

[MolarBoater]

Well, while hanging out on the boat at the dock on the lake with the bilge pump running on cycle mode always pumping out water....and nothing else to do that night.....I got the flashlight out and started to do some thinking.

Where the heck is all the water coming from? New ss bilge plugs properly installed and tight. Baitwell closed off and valve shut. Scuppers above water line with no water coming in. It just seemed water mystically appeared in the bilge pump well.

So after the pump did it's cycle, I stuck my finger in the bilge pump hole. Well, the thru hull fitting from the outside that is. Magically, no water came into the bilge. The pump cycled and quick very fast with nothing to pump. No leaks in the ss worm clamp areas or hose. Water is just entering the thru hull, pouring down with gravity to the bilge pump and out the pump into the well.

Sooooo, I wasn't expecting a bilge pump to let water drain back thru it....shocked.

First thing I would like to do is add a longer hose from the pump to the thru hull and have it bowed UP above the water line to see if this simply keeps gravity from feeding water in. Next, probably time for a new bilge pump.

Anyone ever noticed this happening? I think someone thought this was happening not to long ago but I thought the pump wouldn't let water backflow. Is this correct or is the pump broken?

Ideas?
thanks

[Lazy Loafer]

I don't know if it would be normal for water to flow back through a bilge pump, but I wouldn't be surprised if it did. In my 190 Bay the bilge pump hose leaves the pump and goes aft to the transom, then curls way up as high as it could possibly go into that space of the splashwell beside the wall that separates that compartment from the storage area beneath the rear, port seat, before curling back down where it connects with the through hull fitting. One section of that hose couldn't get any higher above the water line. It came that way from the factory. Has your bilge pump/hose setup been changed since your boat was new?

[k9reno]

I have had to replace the bilge pump in my 210 three times now. All three alow water not pumped all the way out past where gravity will take it the rest of the way out, to flow back through the pump and settle in the blige area around the pump base.

[MolarBoater]

My bilge hose is more of a straight shot and with the thru hull under water at the transom....water just flows back in. This is the factory job as I am wondering how I will get good access in there without cutting a large access in the splashwell. If I am in there, I might as well put in a new pump and keep the old as a back up.
But, it just doesn't seem a bilge pump would allow backflow other than maybe a "dripping" but this is a full blown flow of water. I'll do some more testing this weekend!

[k9reno]

I cant beleive that they put the bilge pump exit underwater.

[jergofish]

No, it is not cool to have a bilge pump through hull exit under water! My 215 has the exit high up on the transom. Bilge pumps are centrifugal pumps and nothing will stop the water from flowing through them. If a lot of water is in the bilge and the through hull is below the waterline but higher than the pump a constant pumping and syphoning will occur until the battery dies and then the syphoning will continue until an equilibrium is reached

Putting a loop in the line will help but will not stop syphoning, it will only work if the bilge pump can put a large enough air bubble in the line to break the syphon, something that bilge pumps are not designed to do.

A better solution is to put another through hull well above the water line and cap off the through hull below the water line or use it for an intake for something.

[JGL]

Molarboater,

I had a 2002 170DC that had a small leak into the bilge area that made the bilge pump cycle on about every 15 minutes. I traced the leak to a cracked fitting on the intake of the livewell pump by putting the garden hose into the bilge and looking for leakage on the transom. It took about 20 minutes and only a small trace of water could be seen dripping from the livewell thru-hull. The crack could not be seen until you disassembled and removed the pump. Triumph sent me a replacement pump, total repair time was about a 1/2 hour.

[NCangler]

Molarboater, I contacted Triumph on your behalf regarding the pump problem and here is what they said:

We did experience some problems with siphoning under the right conditions 2002 and earlier. A flapper valve installed over the bilge dishcharge should eliviate this problem along with a loop in the bilge hose. Have him call Bryant (at Triumph) and we will send him the parts.

Hope this helps!

[MolarBoater]

My appologies to Triumph, after removing the cooler and getting down there I can see a "loop" above the waterline from the bilge pump.

Unfortunately, that does eliminate one of my initial repairs. I read that in general, this is "back siphoning" and that a "vented loop" should be placed to allow air to seep into the bilge hose after the pump is finished to stop the "siphoning" effect "if" the thru hull is below the water line. It is more common on sailboats to have this issue, and , well 2002 or earlier Bay 190's, haha.

I wonder why it has taken 5 years to get bad enough to notice? Still wonder if the bilge pump may be failing since the "automatic" aspect went south years ago? Do bilge pumps allow "backflow"? If they do.....seems like someone would make one that didn't and would be of a better design to upgrade.

Thanks for your help everyone and NCangler, I will call for the parts, I appreciate your help. And, I will more than likely, if there is access, re-route the bilge dishcarge higher above waterline in the future and possibly use the below thru hull for a new raw water washdown intake! One thing leads to another and may end up being OK.

[Genelie]

You know the finger hole test.....the first thing that poped into my head was the little boy who put his finger in the dyke......and more leadks poped up.