ok , I have a few issues going on

[Dalton]

So I decided to take a day and work on the boat. I set out to do a fresh water flush using (sea flush) which is like a funnel (which sits in the sea strainer) and hose that goes into a big bucket. I run the engines and generator and it sucks up the fresh water and I shut it down. 5 gallon bucket for each one.

So….first up is starboard side. I get it all setup, goto flybridge and start it. Run down and water has barely moved. It’s moving, but takes about a full minute or minute 1/2 to go thru 5 gallons. For all I know this is normal.

Go to port side. Same thing but this time it sucks up 5 gallons in about 5-7 seconds.  Which I already realized I ran the impeller dry for 10-15 seconds by the time I could run up and turn the key off. I now know this is how fast it supposed to suck up water and something is clogged on my starboard side.

Both engines have the seamax pumps from 3 months ago. I guess I need to replace the impeller on the one that ran dry for 10-20 seconds.  ??

So there is some issue with my SB side and I’m guessing the heat exchanger is plugged up. Coincidentally this same side threw an alarm one time when I ran at 2000rpm for a bit but the temp gauge was at a steady 175. F it hasn’t done it since.  I thought it was a loose or bad sensor at the time.

Also, this same side needs a new riser (which I have in a box) and probably needs turbo rebuilt as the housing is showing some corrosion. When I changed the zincs I used an inspection camera and the aftercooler looked perfect inside. If this is any indication! So I’m assuming heat exchanger is the cause.

New raw water pumps, impellers, aftercooler looks good. Odds are its heat exchanger! (by the way, my generator heat exchanger was almost fully plugged up but I fixed that)

So I’m guessing I need to stop running the engine as of now! Remove riser and turbo. Send turbo to get rebuilt. While off, clean heat exchanger since its right there! Replace impeller on port side since it ran dry for 10-20 seconds.

Then once together test water flow with engine running. Then at some point work on aftercoolers.

Anything I am  missing? sorry for long post.

Topic

[Rob Schepis]

Heat Exchanger Gasket

ken dalton wrote:
Exchanger –> big gasket –> small gasket –>end cap — > bolt
Can someone confirm?

Your gasket configuration is correct.

Be sure to check the concave in the cap, it may be flat if there was no gum washer. See here:

Heat Exchanger Flat End Cap Fix

[Dalton]

Yes, I know. Thats the important part and I am anxious to see it myself! I need to get the 4 stuck bolts off….Sunday project possibly. I’ll post real good pics once I remove the riser from the turbo.

I’m going to order some parts from the site also.
Question, I inspected my heat exchanger since i had it all out/drained and it looks great to my surprise. But I want to get new gaskets and I see the gasket kit comes with a smaller gasket for the bolt. My current setup didn’t have this.My generator did though.

I assume I need to use this and it would go in this order

Exchanger –> big gasket –> small gasket –>end cap — > bolt

Can someone confirm?

[Tony Athens]

Most important picture is missing—————–The exhaust OUTLET side of the turbo!
Let’s see inside, clear & in-focus..

Tony

[Dalton]

So I got my riser and turbo out of the boat as one unit and need to work on separating them ..those stubborn bolts. But before I did this I wanted to check the impeller and it is fine. I actually removed a hose right after the impeller and pointed it into a bucket. Had someone start the boat and it filled up the bucket in seconds! (only ran engine for a few seconds)

So there is no debris at the water pump or before it. Once I got my turbo off I checked the heat exchanger by removing the end cap on the turbo side and its clean. I’ll check the other side next.

Also removed the hoses going into the aftercooler and the bottom zinc, inspected and its fine. Nice and clean actually.

So for now I’m coming to the conclusion that there is no debris and it was not priming when I did the seaflush system. When I get the motor back together I will run both motors and compare water flow out exhaust at maybe 1500 rpm just to verify.

Now onto my turbo mess…stuck riser, oil leaking from turbo, etc
I was told my riser was bad but from what I can see it looks ok inside….??see pics
i have a new one sitting here anyway.

[Rob Schepis]

Fighting Hoses

Don’t forget the razor knife..

[Dalton]

Thanks Donald. I will check that out for sure! I have a ton to do this weekend. Remove bad exhaust riser, remove turbo (hope its not ruined), look for blockage at/around water  pump, check heat exchanger, and then everything involved just getting to these areas. I think these hoses are going to fight me all the way! I have hose removal tools, heat gun and some patience all in stock.

 

[donald roth]

As the impeller is shredded, the torn off pieces are mechanically forced into whatever opening is at hand, the intake or the outlet being the only options.  When a new impeller is installed, and the motor is running, they get pulled up against the intake grating, and  arrange themselves differently each time, sometimes blocking the intake, other times just restricting the flow.   Remember that while the impeller is being shredded, there is obviously low/no flow.  That’s why impellers shred, whether the cause is intake restriction or impeller failure due to age.

 

When the motor is turned off, there will be a bit of backflow that carries the pieces away from the pump intake grate, so you will never see them unless you disconnect the intake hose from the pump and lower it into the bilge until it is below the waterline and strainer and can freeflow, or close the seacock and take the intake hose clear off if you don’t like saltwater in the bilge.

The impeller rubber does not float, so it sinks down in the hose when the flow stops (the only time you can get a visual).

[Bob Patterson]

Trust John.

I had to completely remove the hose from the strainer to the pump and give it a shake. I got 7 or 8 pieces of impeller and a key for a impeller.Not mine but from the previous owner.It was possibly the cause of the demise of my impeller. Bob

[Dalton]

Donald,

How would impeller bits travel backwards or against the flow? I would think debris would travel towards the aftercooler. I do have an inspection camera so I will put it to good use this weekend.

[donald roth]

Ken, bits of old shredded impellers like to hide on the INTAKE side of the pump.

I know from experience that they can take up somewhat of a permanent residence between the strainer and the pump intake, with some very mysterious and intermittent blockage effects.

 

 

[Bill Desmarais]

I remember the patent

did you ever sell the gazillions of gallons you anticipated?

Did the navy ever use the system?

 

 

[Tony Athens]

EG & seawter pumps

Just an FYI as to seawater pumps with running on antifreeze..  Maybe 7 years ago we got involved in project for the Navy as to figuring  what we could come of with to allow a Sherwood pumps to run dry for about 10 minutes……..After a few months of brain storming, I came up with a automatic liquid injection system into the Sherwood pump so the engine could be started and ran at an idle up to 10 minutes without putting the boat in the water ( these were Military Ribs using  a pair of  QSC 8.3’s with jets that had to be running on the deck of the “Mothership” before launch) . Then,  when launched, the seawater pumps would prime as usual and the system would reset,  and then,  when driven out of the water back up on tne “mothership” the system would restate for a safe shutdown leaving the impeller wet with “secret sauce” again..

To make a long story short, the system was flawless in design & actual operation.. The key to the “liquid Injection” was Propylene Glycol as the basis of our  “Secret Sauce”..  We found that nothing other than a some type of  petroleum based oils worked as good using very small amounts  of liquid to keep the impeller lubed and run heat free for minutes at a time.. EG would have also worked as well that way, but did not meets some of the other stupid criteria the Navy wrote into the spec..

So in the end, just a little  EG on your impeller will give you many seconds to dry run safety..

 

What fun I had!

 

Tony

[William Walter]

Ken I have been winterizing my engines for year by putting my hose in my strainer and then sucking anti freeze thru it after flushing.at times I’ve had the same situation and every time it was a lack of prime.of course I knew ahead of time my salt water side was clean.sounds like your not sure of that and until you are your not going to be sure if you’re doing the right thing .any air will disrupt the water pump in that situation.i doubt if you damaged the water pump as some water was probably present but not enough to prime.if the pump is accessible I’d bleed it as rob said .if not I’ve taken the hose off the  strainer to the pump and refilled slowly.good luck bill

[Dalton]

barnacle growth at the thru hull would not affect what i was doing. I had a tube in the seastrainer and thru hull valve closed so I was only sucking in fresh water from a bucket. I would like an easier solution but first things first.

But I’m not 100% convinced that I just don’t have some blockage in the heat exchanger. It’s hard for me to imagine that with partial blockage it would be enough pressure to expand hoses or push them off altogether. My generator was about 85% plugged up at the exchanger and it actually ran ok, didn’t overheat and no hoses expanded or came off. But I’ve been wrong plenty of times before so …. I just need to take some things apart and I will find the issue. Of course starting with the easiest first.

[james]

check the simple cheap things first

Not sure if you did this or not, but did you check to ensure there was no restriction or barnacle growth on the exterior through hull?    My engines suck down 5 gallons very fast, which is why I have a hose connected and valved system for flushing the engine.  It works pretty darned well, and once in a while, I add a saxltaway mixing component and run that through as well.  The system has paid for itself in zinc’s saved.  I check the zinc’s show very little erosion, and put them back in.

[Dalton]

ok thanks for clarifying!

So I guess another possibility is there is some blockage BEFORE the raw water pump & after the sea strainer. This would explain why the hoses don’t expand, etc . Guess I have some investigating to do. Hopefully its as simple as an air lock or bad impeller but I kind of doubt it..nothing is simple.

[Rob Schepis]

My take on that is that you say temps are normal which they would not be if there were that much blockage and you’d probably either have expanding or blowing off raw water hoses.

No, not with the engine running.  When you setup your flush and get it all filled up (seacock closed) just crack the cover bolts on the pump enough to pull it out a tad and see if air comes out followed by a full steady stream of water, just a bleed is all, then snug it back up and then fire her up and see if she pumps fast like the other engine.

5 gallons in 2 minutes is not right,…in 2 minutes that pump should move 30 gallons or more at idle.

 

[Dalton]

hmm ok I will look. So by your comment I assume the heat exchanger (even if fully clogged) won’t stop the flow of water coming out of the exhaust and thru the whole system. The heat exchanger is just another area of flow but not THE area of flow I take it??

This is a new seamax pump by the way. Just a couple months old, maybe 6 hours on it.  So you are saying I should really loosen the impeller plate, have someone run the motor until I see lots of flow (or don’t see flow) ?

or maybe remove the large hose coming off the pump and run the motor for 5-10 seconds and see if a lot of water flows out?

Not sure of the best way to test the pump itself. I know its working because it did take in 5 gallons but it just took like 2 minutes.

A month or two ago I did this same thing with barnacle buster /water and now thinking back it did the same thing on this engine. Maye the exhaust riser is that screwed up with blockage??

[Rob Schepis]

That impeller will probably be fine ..it wasn’t really “run dry”…but easy enough to remove the cover and take a peek.

That sure was odd with the slow draw on the SB side, does not sound like a restriction in the heat-ex, sounds like the pump was not pumping, impeller damaged, no prime, etc.  I would do a visual check of the pump and then do the SB engine again and check the pump for prime by setting up and filling your flush system and loosening the cover on the pump or the pump ports and make sure it’s flooded.

[Author]

Replies