Water Does not Come out the Exhaust

[Tally Ho]

WOW! What great advice. Thank you.
I am pursuing Hayden's advice and looking into a 12v pump. I figure that I will connect it to the water supply from the seacock, bypass the installed pump and connect it to the water supply tube that normally is supplied by the pump. In looking into it today, I see that I need a pump that is good for continuous duty and have spotted the following:
Seaflo 42 Series 12V Diaphragm Water Pump | Cabela's (cabelas.com)
and thinking about advice previously given in this thread, asked that firm about a filter and was shown one available here:
Seaflo Diaphragm Pump Inline Filter/Strainer | Bass Pro Shops

As far as I have thought it through so far, I don't see any problems and am optimistic about this approach. I will find a 12v source that is only hot when the engine is running.

It sounds like a good idea, but listen to those who have said to be VERY careful about hydro locking the engine. How can you control the pump so that you are not pumping water when the engine isn’t running ?

It seems hard to believe that a small 12 volt pump is going to move more water than the engine pump.

I know you have been fighting this for a long time, but you really need to get to the bottom of the problem. Something isn’t working right. I would be tracing each step of the process until I found the reason it isn’t working….
- Thru hull clear?
- strainer clear?
- hose to pump clear? Could it be collapsing under vacuum?
- heat exchanger clear? How are you checking water flow through the HX?
- mixing elbow clear? You mentioned exhaust back-pressure…could the mixing elbow be plugged? I know this isn’t a Yanmar design, but based on what you said…who knows.

There has to be an answer.

Greg

 

[Tally Ho]

Also, I wonder what the old pump was rated for…the one you linked to pushes 3 gallons a minute. What did the original pump push?

Your new pump looks for pressure drop to turn on the pump…I wonder what that suspected back pressure will do to the pressure switch?

A Rube Goldberg fix is not the answer…sorry.


Greg

 

[Hayden Watson]

It is very true that if you use a 12v pump it must not run if the engine is not turning. The consequences of anything else is water in the cylinders and then you have much bigger problems. Thinking out loud (as I was in my earlier post on using 12v) the simplest way to do that is to connect the water pump to a relay which receives its activation signal from the oil pressure sensor. That way, the pump would not come on until the oil pressure comes up and would stop when the oil pressure drops below the warning pressure.
This is how the external regulator for my alternator works. I turn on the key and there is no power to the alternator but as soon as the oil pressure comes up, the alternator starts producing power.

 

[TimFromLI]

Have you checked the plate that covers the impeller. If it has any grooves in it you can lose the prime. My Ericson had that problem. You can sand the cover down. It must be smooth. not like this one:

 

[priopel]

Just a quick update: the pump arrived but in reading the manual I discovered that it is not a continuous duty pump so have returned it and ordered the Seaflo series 55. I spoke with Seaflo to verify this. So now I wait until the series 55 comes next Wed or Thurs.

 

[Ralph Johnstone]

I know I'm late into this fracas but this is the worst idea I have ever seen for solving a cooling water flow problem. The absolute WORST idea I have seen in 16 years of poking around this forum.

My first question would be "How do you know this 12V pump will deliver the required volume of sea water flow which your engine requires ?" I know my Yanmar 2GM20F pump puts out (5) IGPM at 2800 RPM engine speed. That's got to be one hell of a big 12V pump to put out that much water.

My second comment is that a cheap 12V pump is not going to withstand the many hours you will require of it when running your engine. Your 12V pump will die when you need it most. And that's a 100% guarantee.

The Seaflo pump pump you are looking at is a small pump for potable water. It is a diaphragm pump and not intended to run for hours on end as does your engine.

It has a 48W draw. This will NOT supply the volume of raw water you need.

@Tally Ho has put together the best check list here for what may be ailing your raw water circuit. The answer is somewhere in there and you will find it. You will be cursing yourself when you see how simple it is. Find the source of the problem and don't introduce Rube Goldberg fixes. In this case, that Rube Goldberg fix could very likely destroy your engine.

It sounds like a good idea, but listen to those who have said to be VERY careful

 

[priopel]

You guys are really great and I appreciate all of this. The new pump that is on order, the Series 55, pumps 5 gallons a minute and Seaflo considers it capable of extended, continuous use. To prevent water from getting into the cylinders, I plan to install a switch for the 12v pump and turn on after the engine has started and turn it off before killing the engine.
I think that I have been over every component of the cooling system. Water supply to the pump seems good. I just overhauled the pump including replacing the cover plate. When I tested the output of the pump, I got 1 gallon in 1 minute at idle. But then, it is also delivering water to the manifold and it is a dinky little pump. The local Volvo Penta dealer says that it should be putting out at least 3 gal/min. The rest of the system is good but if the flow from the pump is low, there's hardly a need to look further. The flow looks adequate to me but the pressure is very low. I got it working once by disconnecting the hose from the thermostat where it enter the exhaust. I held the hose down low until water came out then stuck the hose back on. It worked until the next time I started the engine.
I am a novice sailboat owner so am all ears for your excellent advice but this 12v pump sounds like my best hope. The motor is 40 years old so even a temporary fix is attractive. I need to get the boat hauled out and paint the bottom.

 

[Ralph Johnstone]

When I tested the output of the pump, I got 1 gallon in 1 minute at idle.

Please describe the exact location in the sea water circuit where you measured the flow rate of 1 GPM.

Also, is the RPM correct for the engine RPM. In other words, is the drive pulley to driven pulley in the correct ratio. I don't have a manual for your engine but I hope you do.

 

[SycloneDriver]

How about some photos of the pump during the rebuild process? An impeller pump is a simple device that sometimes requires a rocket scientist and a master technician to repair it.

 

[SycloneDriver]

Please describe the exact location in the sea water circuit where you measured the flow rate of 1 GPM.

Also, is the RPM correct for the engine RPM. In other words, is the drive pulley to driven pulley in the correct ratio. I don't have a manual for your engine but I hope you do.

I think he measured it directly at the output of the pump. That's what it looks like in the picture.
The pump appears to driven from the camshaft or intermediate shaft, so not pulley.
The system looks very similar to my old VP2002.
It just about has to be an impeller clearance issue or a worn pump cam.

 

[Hayden Watson]

I think he measured it directly at the output of the pump. That's what it looks like in the picture.
The pump appears to driven from the camshaft or intermediate shaft, so not pulley.
The system looks very similar to my old VP2002.
It just about has to be an impeller clearance issue or a worn pump cam.

Some pumps have a removable / replaceable cams. He should make that the cam is in place. A photo of the inside of the pump would be helpful for diagnosing the problem.

 

[SycloneDriver]

Some pumps have a removable / replaceable cams. He should make that the cam is in place. A photo of the inside of the pump would be helpful for diagnosing the problem.

I looked at a couple of rebuild kits for his pump and they listed the cam, so it should be replaceable. It also might be a sleeve bearing instead of ball, I wonder if the shaft is loose in the sleeve.

 

[Ralph Johnstone]

Undaunted, I removed the thermostat housing, connected a clear poly tube to the water supply line with the other end in a bucket. I ran the engine at idle for one minute and it produced one gallon of water.

Thanks @SycloneDriver , for that info. It appears that there is some attempt to measure the pump output right at the pump outlet, although I would like to see the tubing in place.

Unless my eyes deceive me, the inside of that pump appear to be excessively corroded.

That pump interior also looks to be cast iron.

@priopel , please supply a clear picture of the pump interior. And we will need a picture of the pump interior from your engine manual. If you don't have a manual, search this site for one.

 

[SycloneDriver]

Thanks @SycloneDriver , for that info. It appears that there is some attempt to measure the pump output right at the pump outlet, although I would like to see the tubing in place.

Unless my eyes deceive me, the inside of that pump appear to be excessively corroded.

View attachment 210479

That pump interior also looks to be cast iron.

@priopel , please supply a clear picture of the pump interior. And we will need a picture of the pump interior from your engine manual. If you don't have a manual, search this site for one.

I could be wrong but I think that is the inside of the thermostat housing.

 

[Ralph Johnstone]

I could be wrong but I think that is the inside of the thermostat housing.

Until I see otherwise, I don't think we have any information as to what the pump rate of discharge is.

 

[priopel]

Hurray! After installing a 12v pump, I now have water coming out the exhaust.
Because the water pressure is so much greater, I now have leaks at those pesky seals along the water supply pipe. The design of having flat washers abutting the end of a copper pipe to effect a seal makes no sense to me especially considering that there is nothing connecting the pipe. I improved on this by taking some conical washers and shaving them down to the right shape with sandpaper. This reduced the leaking but not entirely. I then formed a piece of wood as a wedge and tapped that into place under the point where the water supply pipe enters the manifold. This again reduced the leakage but not entirely. At this point, I decided to call it a day and smile at the fact that I now have water coming out the exhaust.

 

[priopel]

I couldn't attach this pic to the above message so am posting it here.

 

[SeaCure]

I don’t know Volvo well at all. Did anyone check the thermostat. You can have best pump in the world but a blockage upstream will stop it from primming. Is it possible to self prime with some add on?

 

[priopel]

To prime the cooling system, I inserted a flushing "T" along the hose from the thermostat to the exhaust. But this is unnecessary since installing a 12v pump. I have great water pressure now and only need to fix one leak along the water supply tube where it enters the manifold. Thanks for your thoughts.

 

[Puesta del sol]

Maybe crazy - we fought water flow issue for a few years. We had the boat for 7+ with no issues, the heating problems. No broken impeller pieces etc. Cleaned all the parts ... still issues. Finally found a bunch of broken impeller pieces on the intake side. Must have shifted just right after 7+ years of no issues...Crazy.... Hard to believe the pushed backwards versus pushing foward.