Salt water wash down

[Denis]

I am on my second pump, but I guess I will change the pump again and see if the third time is a charm.

[Mariner]

Clarify for me here. Did the second pump ever work? If not, then I suspect your problem is not the pump. Either that or you somehow got a bad pump from the manufacturer, in which case they should replace it for free.

Again, I would "bench test" the pump in a controlled environment and see what happens.

Is there any chance your replacement pump is not a self-priming model?

[JackK]

Denis -

If you believe it is a priming issue, try filling the hose with water prior to connecting it to the pump. Backwards priming it might just prove whether you have a priming issue or not.
From my RV days, I have a hand pump that you can press onto the hose bib and pump fluid back to the pump. You might have to disconnect the hose from the pump just to release the air and allow the water in.

Just a thought.

Jack

[Denis]

The second pump never worked and I have no idea if is a self priming pump, I didn't know there was a difference. I used a fresh water pump could that be my problem?
It is a bear to take out but when I do I'll check it on a bench to see if it works there. I find that as I get older, I can work less and less time upside down, standing on my head.

[Mariner]

Well, for starters, a freshwater pump probably won't stand up to the saltwater going through it. I have no specific product knowledge, but I would think that the shaft on a saltwater pump would be stainless or at least bronze, while on a freshwater pump, it mught just be regular steel.

Self priming pumps will pull water up, even when they start with only air. A non-self-priming pump, must already be flooded with water to start. A freshwater pump, used for the boat's onboard freshwater system, is usually not self priming. It is simply mounted low enough in the boat so that gravity feeds the water from the water tank into the pump, and then it pumps it up to the faucets from there. Used as a washdown pump, a non-self-priming pump would work, so long as it was mounted below the waterline, and there was no air gap in the line. Of course, no responsible builder would install it in this fashion, because a failure would hole the boat, and flood the bilge, eventually sinking the boat. So, for that reason, saltwater washdown pumps are usually self-priming. If the pump you got is not self-priming, that could very well be your problem.

If what you have is something like this:
http://www.westmarine.com/webapp/wcs/st ... lassNum=74

What you need is something like this:
http://www.westmarine.com/webapp/wcs/st ... assNum=234

They look the same on the outside, but you'll notice that the second one says "self-prime 6'". Huge difference.

[Denis]

I'll bet that is my problem, I used a fresh water pump that is not self priming and I just assumed that since it still didn't work after I put the new pump in that my problem was else-where. I'll try another new pump that is self priming this time. Thanks for the help. Denis

[Denis]

I installed another new water pump, but this time I made sure it was a self priming pump and that took care of the problem.
Thanks for the suggestions. I just assumed that all pumps made for a boat were self priming, but I learned something new today. Thanks for the help. Denis