Another Raw Water Pump Concern

[Bod6866]

I have a 2003 Air Nautique 206 with the excalibur 330. My raw water pump is not working. I have read as many posts as I can find and have tried everything. I hooked a hose directly up to the water pump to eliminate the strainer and all, still no water flow. I unhooked the hose on the backside of the water pump and I have no water coming out of the water pump. I installed a new impeller and still no flow, old impeller didnt look bad. I don't see how this water pump can physically be installed backwards. Not sure if it is supposed to work this way but I did remove the water pump and filled it to make sure it wasn't leaking internally and it would not hold water. It would just flow through the water pump. Maybe that is normal but it doesn't seem right to me. I am at a complete loss where to check from here or what to do.

[NautiqueJeff]

Probably a dumb question, but is the belt installed?

[Bod6866]

Haha yes it's installed and adjusted properly. At this point there is no dumb questions. This system is not that complicated. Well it's not supposed to be.

[Bod6866]

So this
so this is not in My water pump. Could that be why it is not creating vacuum? Leaking past the impeller ?

[behindpropellers]

Is there a valve by the hull on your boat that is closed? Should be right at the through hull fitting.

[Bod6866]

That valve is open. I hook a hose right up to the water pump and eliminated the strainer, tranny cooler and all other hoses to the water pump. I guess I can put some silicone on the water pump cover to make sure it is not leaking but I am pretty sure I got it sealed up.

[NautiqueJeff]

It is possible that you might have the wrong impeller. Early Excaliburs (non-serpentine belt) should use RP061017. That one should be used through 2004, but be sure your engine has two belts if you use this one. If it has one belt (serpentine), use the one below.

Later (serpentine belt) Excaliburs use RP061022, which is smaller and would not pump water on the non-serpentine engines. Are you sure you didn't install the wrong one? It should be a very tight fit.

[Bod6866]

It is the 2 v-belts not a serpentine belt. I did use impeller RP061017. I would say it was snug but definitely not tight. I was surprised how easily it went in compared to my old mastercraft. Is it possible the inside of the water pump is just worn and needs replaced?

[Rednucleus]

Please post a pic of the installed impeller so we can evaluate it's fit

[Bod6866]

Sorry I was away for a bit. Here is a pic of the impeller in the water pump and then without the impeller. I have checked and double checked and there is no air leak before the water pump.

[TechBeer]

That looks correct to me. I know that if there are ANY air leaks upstream of the impeller it will struggle to pull a vacuum. I had all kinds of trouble with that one season. I had to get it up on a plane to force water through the impeller and then it would be fine. Almost like a priming process. Also if I let is sit for a while and then idle it for a long time sometimes it will get hot, like the water it running out over time. The minute I get it up on a plane it's fine. Any damage/wear to the impeller will cause this also.

If you get it all together and in the water you might try this. Start it up and get it up on a plane (before it overheats) and see if water is coming out the exhaust. This would be a clue.

[Scooter G]

That valve is open. I hook a hose right up to the water pump and eliminated the strainer...

Was the engine running when you had the hose hooked up?

[core-rider]

All of that looks correct. If you have a hose connected straight to the pump, even without the engine running I'd imagine you'd get a little water through the pump just from the water pressure on the hose pushing past the impeller.

Only thing I have to add is make sure the inner metal hub of the impeller hasn't spun in the impeller itself causing it not to spin the actual impeller when the engine is running.

[Bod6866]

Ok let me make sure my explanation is correct. I unhooked the line that come off the strainer and put it in a bucket of water. So it is a single hose that goes from the bucket to the raw water pump. I made sure the connection was tight at the water pump and not letting in any air. I made sure the cover was tight and not leaking any air. Even with revving up the engine a little it still will not draw any water. I am about to order a new pump just to eliminate that as an option. This system can't be that complicated.

[core-rider]

Ok let me make sure my explanation is correct. I unhooked the line that come off the strainer and put it in a bucket of water. So it is a single hose that goes from the bucket to the raw water pump. I made sure the connection was tight at the water pump and not letting in any air. I made sure the cover was tight and not leaking any air. Even with revving up the engine a little it still will not draw any water. I am about to order a new pump just to eliminate that as an option. This system can't be that complicated.

IMHO this is you issue. Every time I've replaced the impeller the hoses come off to remove the pump from the engine. Of course, that hose coming from the strainer/heat exchanger drains of water. I always have to "prime" the pump with water again by removing the top hose on the heat exchanger and pouring water in the hose until it comes out the top of the heat exchanger. I then replace the hose. I also put Dawn soap on the impeller just to give it a better chance at life till the water is flowing well.

The way my hoses are routed from the seacock it goes up about 2', then through the stainer, down about 1' through the heat exchanger, and then to the raw water pump. A dry pump can't pull water that distance as it needs the suction of water in the hose.