2017 Mondo - No RAW Water Flow Question

[audisnapr]

Quick question: with the water impeller out of the housing and the cover plate off, should water, via a garden hose connected to the inlet on the bottom of the boat, push water into the impeller housing with or without the engine running? I'm getting nothing - no flow.

I thought maybe the impeller was toast but I pulled it out and it's fine... well not any longer now that I pulled it out but it was fine :D

Not so great day on the lake yesterday - if you can even call it that. Boat started smoking and then overheating as soon as we got past the no wake zone after leaving the dock. I saw 235 degrees at some point.

[Holdmybeer]

Check the ball valve on the thru-hull where the water is sucked in. If some how it got closed you will overheat quickly.

The water inlet is the lowest point in the system and the hose would have to push past the v-drive and transmission before water would be in the raw water pump. Follow your lines from thru hull up to pump.

A clog will cause this also. Most likely the heat exchanger. Remember if you are clogged upstream you cannot push the air out of the system to get fresh water in. 235 is scary but if that is all you got to, you should have avoided damage.

[audisnapr]

I see. Thanks. I just assumed the hose from the thru-hull pick up/inlet went directly to the water pump.

I noticed the ball valve handle when looking through the v-drive access hatch. It's currently oriented to be in line with the hose and doesn't look to have been touched, ever. I'm assuming it's in the open position in its current state.

When testing to see if water flows, I started the engine and it ran perfectly fine (only ran it for less than 30 seconds) but still no water getting to the pump housing from the garden hose via the under hull pick up/inlet.

[Holdmybeer]

The pump has to draw water through the v-drive first. It takes a minute before coming out of the exhaust.

Are youbgetting water in the bilge? Missing or loose plug would cause some issues also.

[audisnapr]

Got it. I was hoping the water pressure from the garden hose (using a fake a lake) would push water through the system and come out of the pump housing since I had pulled the cover and impeller. Instead, the water was just spraying along the bottom of the hull where the fake a lake meets the hull. I didn't see any water in the bilge area.

Ideas on the next steps? Start pulling hoses to see what I find?

Where does the heat exchanger fall into the mix? I assume it's also cooling oil so I would need to make sure I am pulling the correct hoses.

[VA LSV]

Where does the heat exchanger fall into the mix?
Follow the large hose leaving the V-drive and the next thing it connects is the transmission heat exchanger. Pull the hose off and use your finger to clean out any debris.

[HFarr]

Can you try backwashing from the raw water pump with the hose. It may blow any clog out if it's not too far into the inlet on the bottom of the boat. But you may have to be creative with the connection to make that work.

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[Holdmybeer]

VA LSV is correct.

Just follow hoses up.
Thru hull to v-drive
V-drive to Trans
Trans under engine to raw water pump.
Water pump to coolant heat exchanger - canister on starboard side of raw water pump

Canister to exhaust manifolds

The u-pipe under the pump is a low spot that can catch debris also. There is a blue plug in this pipe to pull and check for water.

Also, you can pull the water flow sensor out and check for a clog there. It has a key ring on it and is tight to get out.

[audisnapr]

Thanks, all. I appreciate the quick responses. I'll poke around some more and start following the lines and see what I can flush out... right after it's not 100 degrees and 95% humidity.

[HFarr]

If you are anywhere around me you will be waiting a while for that to happen! A cool low humidity day that is! LOL!

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[audisnapr]

After a few days of high temps and humidity, I finally got back out to the boat today to check things out. With my head held down in shame, I'm reporting back to share that it was indeed the main raw water line valve in the closed position. The valve had been closed by the tech who winterized the boat at the end of last year. This is the first time they've done that in the six seasons we've had it winterized by this shop.

Originally, I confused the raw water thru-hull inlet for the ballast inlet, which was in the open position. When I went out today to check, I remembered what you all had said about the raw water inlet going directly to the v-drive and when I reached in through the hatch, and felt that the handle was perpendicular to the hose, unlike the others, I knew right then it was closed. I emailed the shop on Monday and they too confirmed that their tech remembers closing it - I didn't trust his account because he mentioned the valve was near the front of the boat which made no sense to me.

Anyway, mystery solved. Makes perfect sense now. Definitely odd for the raw water inlet to have clogged within minutes of running after it had been winterized.

I replaced the impeller and seal with a new one - so at least that's done.

On the bright side, thanks to you all, I learned a bit more about the water system. I learned how to swap the impeller which I hadn't done yet.

Engine sounds and runs smoothly. Hoping for no lasting damage due to overheating.

Thanks for the help.

[Holdmybeer]

Do not beat yourself up too bad....your friends and family will do that enough...hahaha

Good you learned some things in the process that is what life is about.
As for the temps, if 235 is all you saw the boat should be fine. Did you antifreeze tank overflow? If you have to add antifreeze there is a certain way to do it so it doesn't airlock and overheat. I can help you with that also, so just ask.

Have a good weekend

[audisnapr]

Thanks again. The antifreeze burped over a bit but the reservoir is still half full - it should probably be topped off. Is there a procedure to top it off even if the reservoir has fluid in it?

[Holdmybeer]

If the reservoir is still above the hose you are good.
It only is an issue if you get air in the system. Just top off the container and you are good.

[MJHSupra]

After you run the boat once or twice, keep an eye on the reservoir levels. If you have air in the system, it usually purges, then you need to add a little more fluid - but you are probably good.

[MJHSupra]

After a few days of high temps and humidity, I finally got back out to the boat today to check things out. With my head held down in shame, I'm reporting back to share that it was indeed the main raw water line valve in the closed position. The valve had been closed by the tech who winterized the boat at the end of last year. This is the first time they've done that in the six seasons we've had it winterized by this shop.


It's a common thing after winter storage for people that do not winterize their own boats. I see it on social media. Be glad that was the issue.