Cooling System Issue - Not sucking water - 2006 22Ve Marine Power

[okiepilgrim]

Getting the boat ready for the lake after winter and when I fired it up I noticed it wasn't pulling water. My "fake a lake" is a giant bin with 2 hoses pumping in and a line direct to my raw water intake.
Checked that there's a good seal from my raw water filter to the water bin.
Checked the transmission cooler - clear and basically appears no issues between intake and impeller.
I did change the impeller a few weeks ago when there was some nice weather, but I took off the cover and turned it over and confirmed the new impeller is spinning.
Also, if I hold the intake hose well above the boat and spray the hose directly into it, water does get through the system, but it doesn't seem to get any "suction" to pull water itself.
I also removed the block side of the impeller "output" line and started it up and similarly confirmed that it's not pumping water. (A couple of gushes will come out at startup, but then nothing).
I've seen a mention of needing to replace the impeller housing if there's no suction. Does this sound right? Believe it's a Jabsco? 2006 22Ve Marine Power 5.7.

The impeller is the water pump, right? There's not a separate pump somewhere is there?

Any thoughts/help are appreciated!

Thanks,

Blake

[chpthril]

The engine does have a circulation pump like any regular engine does, but this would not effect the raw water impeller pump drawing water.

Is the trans cooler drain plug in? Some remove it to winterize, others just pull a hose off one side.

raw water filter housing leaking? May be cracked?

[okiepilgrim]

Pulled the hose to drain, so drain plug should be in. Also could not feel any water around the housing indicating it leaking.
Am attempting to swap back to the old impeller just to see, but man those things are hard to get out - especially at that angle/reach... To be cont'd later this evening.

[okiepilgrim]

Ah, misread that. I'll double check the raw water filter housing. It is plastic. But I didn't notice significant water running into the bilge. Oh, I also basically sucked on the "fake a lake" hose I have attached to that and that seemed to have a good seal/held the vacuum.

[chpthril]

Out side of wrong impeller, it sounds like its sucking air somewhere.

[okiepilgrim]

So, after failing to get the new impeller out, but feeling like that wasn't the issue anyway, I put the cover back on the housing and double checked everything again. Couldn't help but feel like I was chasing my tail, so I fired it up again. Still wasn't pulling, but there was a faint suction for a moment. So knowing it pulls more water at higher RPM, I thought I'd give a little throttle and just see. Sure enough, soon as I gave it a little gas it started drawing water.
Not sure if it's because I just "summerized" it or if there is some air getting in somewhere, but I ran it for a good 10 mins and all seemed fine. So, guess I'll keep an eye on it, but think it may have just taken a bit to get some suction going.

As always, thanks chpthril for weighing in with your thoughts!

[Bamer]

Depending on how long you ran without water getting to the impeller, you probably should pull it and inspect it. I know it’s a pain to get out, but it will be time well spent if the brand new impeller has been overheated/damaged.....better to find it now than after you over heat


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[okiepilgrim]

We're talking about a minute or two at a time. I also took a q-tip and added some lube when I had it open, but still a good point. I'm gonna grab a puller because it's just not worth the time/frustration without.

But on a follow-up note, got it on the water finally yesterday and seemed to be the exact same behavior. Engine got warm pretty quick and exhaust manifolds started to get warm as well, but then once again it seemed to "kick in" and that 50 degree Colorado water cooled it right off. Was fine the rest of the day.
My experience has always been that the impeller starts pulling water straight away, regardless of temp. But does the thermostat somehow control how much water gets pulled? Is it possible there's a thermostat issue? Anyone think of any reason it would not suck initially and then start sucking? Almost like it has to "build up" the suction.

[chpthril]

No, you have a raw water pump problem.

[ajward]

Did you clean out the Trans Cooler screen located on the inlet side when you remove the hose. Unless you have really skinny fingers, you need a needle nose plier to get in there. Here is what I pulled out of mine one year...

[ajward]

Trans cooler clog.jpg

[ajward]

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[okiepilgrim]

Wasn't even aware there was a screen in there, but I'll take a peek. However, a previous owner added a raw water strainer, so I'm hopeful it would catch anything like this before ever hitting the trans cooler.
I still have a ghost somewhere but I don't think it's the water pump. My best guess is just rust/debris in the cooling system - primarily on the port side. Bought a traditional fake-a-lake and water moves through, but more on starboard than port. It's never over-heated or alarmed, but despite that and the fact I run ethanol free gas, it vapor locked on me a few times last summer. I now run the blower full time and hand-check the manifolds (primarily the port one) and/or idle before shutting it off.
I got some rust flakes out when I winterized and a bunch more dry flakes just the other day when prepping it for this year. Not sure if that'll make much difference, but short of pulling off a manifold and cleaning everything out, I'm not sure what else to try.

[Jetdriver]

Bite the bullet and replace your impeller. For $35-40 you eliminate that possibility it’s bad. I’ve also had the impeller housing cover not make a good seal when trying to reuse a gasket after opening it up. It’s best to go new on both each time you open it up. Just my opinion though. If it’s been run dry they go bad quickly.
The impeller is easily pulled with a sea dog impeller puller. Well worth the $50. Makes the job easy and you don’t risk damaging the housing gasket mating surface with a screwdriver, pliers or whatever your currently using.
The trans cooler can collect debris on the intake side of it, pop the hose off and clean it out with your fingers. Besides those things it really only leaves your raw water strainer or a bad seal at your water pick up. A fake a lake is a cheap tool that works well.