Water circulation problem

[Dampsquid]

30 minutes ago, shawndoggy said:

I don’t think that is right. 

Try hooking up your garden hose to the flush pro with the bypass gizmo piece in and the water  doesn’t run out the bottom?

I had the hose connected without the bypass gizmo. Garden hose pressure is easily enough to open the check valve into the flush pro. Then there’s another valve stopping back flow out of the boats inlet. If we’re talking about the same bypass gizmo, it’s job is to push the hose connection valve open, because when on the bucket there’s insufficient pressure to do that.

The instructions say to use the gizmo with the garden hose if city pressure is insufficient to open that check valve. Now I think about it, I believe I now know why they say to open the garden hose supply to 1/3 initially and then full once the engine is started... this must reduce the stress on the back flow prevention valve.  I’m going to re read the instructions now...

[Michigan boarder]

9 hours ago, Dampsquid said:

I had the hose connected without the bypass gizmo. Garden hose pressure is easily enough to open the check valve into the flush pro. Then there’s another valve stopping back flow out of the boats inlet. If we’re talking about the same bypass gizmo, it’s job is to push the hose connection valve open, because when on the bucket there’s insufficient pressure to do that.

The instructions say to use the gizmo with the garden hose if city pressure is insufficient to open that check valve. Now I think about it, I believe I now know why they say to open the garden hose supply to 1/3 initially and then full once the engine is started... this must reduce the stress on the back flow prevention valve.  I’m going to re read the instructions now...

I agree with all of that, I had the same process and same procedure when I had a flush pro up until this spring.

[Michigan boarder]

10 hours ago, Dampsquid said:

Agreed, to a point. Since the intake is below the water line this is true. But when stationary the water will only go up the tube to the same height as the waterline. In my boat that’s approx floor level. The impeller then needs to lift the water the additional height to the thermostat housing.  With the bucket connected to the Perko, the bottom of the bucket is already above floor height, plus the extra pressure from the water in the bucket, say an additional 10-12” of head... I’m already above the impeller height, meaning it has less work to do than when sitting in the lake.  There’s a huge difference between any static pressure in the inlet pipe from the lake versus that of the city supply  

Notwithstanding all of the above... last year it sucked a bucket dry in around 20-30 seconds,  through  a fake a lake, and while the bucket was on the driveway.  Something has changed, and not in a good way.

Others have said they’ve never had luck with the bucket idea. I wonder then how their boats stay cool on the water. My guess is they don’t sit idling for long, if they did, they’d over heat. It’s the extra (dynamic) pressure created in the system by the boat moving at speed that’s forcing water through the system. Just like the city supply has enough pressure to do the same apparently. 

Thanks for taking the time to reply..  

Good point, water level is the limit.

FWIW, my boat idles a lot, especially if filling a bunch of ballast bags for a surf set up, and the temperature doesn't budge.

[formulaben]

14 hours ago, Dampsquid said:

Others have said they’ve never had luck with the bucket idea. I wonder then how their boats stay cool on the water. My guess is they don’t sit idling for long, if they did, they’d over heat.

If you're overheating at idle you have a problem.  There's a big difference between sitting in the lake and asking the impeller to suck it up out of a bucket.  I am at idle A LOT due to night cruises and a long no wake zone where I frequent and it's never an issue.

[Dampsquid]

I may have found the problem.

TLDR: If I take all the pipes off the raw water pump, should I be able to blow (by mouth) through the pump at all?  I'm thinking no; but I can quite easily.

Longer: This has been doing my head in!  Decided to start at the beginning again.  Followed all the hoses from inlet to exhaust, pulling them and checking for any kind of obstruction.  Nothing.  So it just has to be the pump.  But it looks fine, and the impeller has been changed in any case.  But no water - it simply can't be anything else.  So pulled it off altogether with the plan of putting it on the bench and spinning it with a cordless drill to see if it would pump anything at all.  Before figuring out a gizmo to connect to the drill I picked it up and just blew through it.  I wasn't expecting it to pass air, but it does...

[Chaabo]

I’ve never given my raw water pump a blowjob  but me thinks that you shouldn’t be able to blow air through it.

Pump or impeller is bad. Would also be the easiest and most logical explanation for the situation you are experiencing.

Edited October 13, 2018 by Chaabo

[formulaben]

1 hour ago, Dampsquid said:

I may have found the problem.

TLDR: If I take all the pipes off the raw water pump, should I be able to blow (by mouth) through the pump at all?  I'm thinking no; but I can quite easily.

Longer: This has been doing my head in!  Decided to start at the beginning again.  Followed all the hoses from inlet to exhaust, pulling them and checking for any kind of obstruction.  Nothing.  So it just has to be the pump.  But it looks fine, and the impeller has been changed in any case.  But no water - it simply can't be anything else.  So pulled it off altogether with the plan of putting it on the bench and spinning it with a cordless drill to see if it would pump anything at all.  Before figuring out a gizmo to connect to the drill I picked it up and just blew through it.  I wasn't expecting it to pass air, but it does...

When you turn the pump, hold it so your palm covers on the inlet side.  You should feel a decent amount of suction when you turn it.

[Dampsquid]

33 minutes ago, formulaben said:

When you turn the pump, hold it so your palm covers on the inlet side.  You should feel a decent amount of suction when you turn it.

When I turn it by hand?  I feel basically nothing.

[UWSkier]

This is the strangest winterization thread maybe ever...

[formulaben]

On 10/6/2018 at 1:16 PM, Dampsquid said:

Boat is 2000 sportster. Started winterizing it, connected fake a lake to hose to warm engine to change oil. Didn’t notice any particular problem.  Next, I put fake a lake hose into a full bucket, along with hose.  This is the way I got antifreeze into the engine last year, without issue. I noticed the engine isn’t sucking water out the bucket. This despite being well primed due to the previous direct connection to the pressurized supply from the hose. Last year it would empty the bucket pretty damn quick. 

I checked the transmission cooler strainer, nothing there. Checked the impeller, noticed some of the vanes have lost their spring, and not pushing against the pump body.  http://imgur.com/KunnC6i 

So I replaced it with the one intended for next season. Retested, same problem. I also don’t have much water coming out the exhaust, at least not as much as I remember last year. At idle there’s pretty much none. So it seems that there’s insufficient water circulating. I did let the engine get above 160 so the thermostat should have opened. But I’d expect a good quantity of water to be expelled out the back regardless of what the thermostat was doing?

First impeller was toast per picture, and this is where the 2nd one got shot if you say the pump was getting hot.

 

On 10/6/2018 at 4:47 PM, justgary said:

It's a lot easier to pump air than water.  It doesn't take a very big air leak to make your pump quit lifting water.  You have a leak. 

Totally agree with @justgary that you have an air leak in your pump.

 

10 hours ago, Dampsquid said:

So pulled it off altogether with the plan of putting it on the bench and spinning it with a cordless drill to see if it would pump anything at all.  Before figuring out a gizmo to connect to the drill I picked it up and just blew through it.  I wasn't expecting it to pass air, but it does...

Well, I missed that earlier, but that confirms your leak for sure.  The leak is allowing air in the pump and it's not priming and then overheating, thereby ruining your impeller.  Could be a bad seal on the cover plate, a leak in the shaft seal, or the impeller is either bad/damaged.  At this point, I'd either get a new seal and rebuild the pump or just buy a new one.

[Andrew63]

On 12/10/2018 at 9:05 AM, Dampsquid said:

Could it be the main engine water pump has completely failed?  That's the only thing I can think of, but there's no odd noises at all, and if it is the pump it must have failed taking the boat to the landing when I pulled it off the lake for the season.  The impeller is still OK even though it's taken some abuse.

If anyone has an ideas where to go next with this, please do tell.  I'm stumped.

Thanks in advance.

There was a post awhile back showing the cast iron  circulation casting on the back of the engine circulation Pump had split.

cracked allowing the shaft to spin freely but no water moved around the engine.

when you mentioned the boat would heat up at idle but cool down with a bit of throttle this season had me thinking this could be the culprit. But, this would not explain the raw water pump not sucking water.

i have a T fitting with a tap along my raw water inlet line before the raw water pump. It has a garden hose fitting just befor the tap.

when flushing all I do is hook up a garden hose, open this tap which allows the water to flow out the raw water inlet, start the engine & water is sucked straight thru the raw water pump then the engine.

[Michigan boarder]

I'll complicate this even further.  I know of a guy that has removed his circulation pump altogether (part of a large effort to reduce engine weight) and only uses his raw water pump to push water thru the engine, and it works.

[boardjnky4]

1 hour ago, Michigan boarder said:

I'll complicate this even further.  I know of a guy that has removed his circulation pump altogether (part of a large effort to reduce engine weight) and only uses his raw water pump to push water thru the engine, and it works.

That's dangerous. Cool water may get to the housing where the sensor is, but that is not guaranteeing that water flows throughout the entire motor correctly.

[Bozboat]

On 10/14/2018 at 6:05 AM, Andrew63 said:

There was a post awhile back showing the cast iron  circulation casting on the back of the engine circulation Pump had split.

cracked allowing the shaft to spin freely but no water moved around the engine.

when you mentioned the boat would heat up at idle but cool down with a bit of throttle this season had me thinking this could be the culprit. But, this would not explain the raw water pump not sucking water.

i have a T fitting with a tap along my raw water inlet line before the raw water pump. It has a garden hose fitting just befor the tap.

when flushing all I do is hook up a garden hose, open this tap which allows the water to flow out the raw water inlet, start the engine & water is sucked straight thru the raw water pump then the engine.

Circ pump won’t make any noise unless you take it off and shake it

 

Edited October 15, 2018 by Bozboat

[Woodski]

@Dampsquid:  The raw water pump is a positive displacement pump, you should feel suction on the inlet side and pressure on the outlet when you turn it over by hand.  If you don't there is a leak allowing the air to escape via another path.  Have you looked at the housing for scoring, cracks, that is a likely possibility.  I have also seen a shorter impeller from some sources, that would also allow an air path that would defeat the function of the pump.  Also, make sure the impeller is actually turning when you spin the shaft, sometimes the vanes can separate from the inner housing.

@boardjnky4:  How so?  The set up provides water input to the same intake openings in the engine block, the bypass hose is sized to control bypass flow to the exhaust manifolds during t-stat closed or warm up and not hinder water flow to the block.  Water path is unchanged w/o circulation pump.  The head gasket does most of the water distribution control via the hole pattern for water passing between block and cylinder heads ensuring water gets to the back part of the block.  Actually, in a sense safer as the system is simpler and no way a failed circulation pump (think cracked circ. pump impeller) can cause a problem since it is not there and no springs/balls to corrode or fail (Mercruiser setup) for the bypass circuit.  BTW - 600 trouble free hours on the system.

[mackie12]

drop a pump in the bucket, use this as your feed line to the boat and be done with it. Lots of boats (pumps) cannot pull from the bucket as they are not designed for this (NPSHR).  I do the same thing as @formulaben does except I do not have fresh air exhaust or whatever that thing is called, built something similar out of PVC and such.

 

[Dampsquid]

6 hours ago, Woodski said:

@Dampsquid:  The raw water pump is a positive displacement pump, you should feel suction on the inlet side and pressure on the outlet when you turn it over by hand.  If you don't there is a leak allowing the air to escape via another path.  Have you looked at the housing for scoring, cracks, that is a likely possibility.  I have also seen a shorter impeller from some sources, that would also allow an air path that would defeat the function of the pump.  Also, make sure the impeller is actually turning when you spin the shaft, sometimes the vanes can separate from the inner housing.

I can't feel any suction on the inlet, or 'push' on the other.  The pump cover was quite badly scored, so I sanded that smooth once again.  Hasn't helped.  It may be the back of the pump isn't in too good a shape, but I'm not near it now.  I was about to order a new one... but your comment on having seen impellers too short has me worried.  It certainly seemed to be the right size, flush with the pump housing, but now I'm thinking that gasket has a little thickness, perhaps the impeller should sit proud of the housing by the gasket thickness?  It must only be 1/5 mm or so, but that could make all the difference.

[formulaben]

4 hours ago, Dampsquid said:

I can't feel any suction on the inlet, or 'push' on the other.  The pump cover was quite badly scored, so I sanded that smooth once again.  Hasn't helped.  It may be the back of the pump isn't in too good a shape, but I'm not near it now.  I was about to order a new one... but your comment on having seen impellers too short has me worried.  It certainly seemed to be the right size, flush with the pump housing, but now I'm thinking that gasket has a little thickness, perhaps the impeller should sit proud of the housing by the gasket thickness?  It must only be 1/5 mm or so, but that could make all the difference.

Your picture of the first impeller shows the correct part number.  Could be that it was "toast" due to sitting in the pump and the vanes got curved, but that doesn't explain the 2nd impeller failure.  I would install a new impeller and do the suction test again.  New or rebuilt pump is in order if it fails that test.

[Dampsquid]

Thanks for the info on part number.  I ordered a new pump from skidim, should be delivered before I’m home from my current work trip. I’m confident the second impeller is good, it’s the same part number as the picture, and really is indistinguishable from new.  

I’ll post again after fitting the new pump, hopefully this weekend coming.

[formulaben]

11 hours ago, Dampsquid said:

Thanks for the info on part number.  I ordered a new pump from skidim, should be delivered before I’m home from my current work trip. I’m confident the second impeller is good, it’s the same part number as the picture, and really is indistinguishable from new.  

I’ll post again after fitting the new pump, hopefully this weekend coming.

Keep in mind that if the impeller is spinning on its own internal shaft it will still look brand new and you won't be able to tell it has failed unless you turn the motor with the cover off (use Dawn dish soap and water to lube the impeller and pump assembly.)

[Dampsquid]

OK, final post for anyone with a similar problem in the future...

I replaced the raw water pump with a new one.  As mentioned previously I could blow air through the old one, not a huge amount, but enough to think this showed a problem - think approx the same as a small diameter straw.  Turning the impeller didn't make any difference to how easy it was to blow through.  The impeller is fine.  

The new pump can also have air blown through it, but not nearly as much.  Also turning the impeller changes the ease of which air can be passed down to almost none at all.  Knowing this may help others diagnose pump issues.

On the boat, the new pump is moving water from a bucket placed on the floor of the boat through the engine - so success.  But, it's not as much as last year.  So I think there may also be an issue with the circulation pump.  My theory is after the thermostat opens there should be a higher flow rate out the exhaust than compared to the raw pump alone - and I'm not seeing that.  Come spring I'll have that pump off to inspect, but right now it's getting cold, and I'm going to shrink wrap the sporty before cold turns to freezing.

My thanks to all that took the time to reply!

Edited October 23, 2018 by Dampsquid

[formulaben]

On 10/6/2018 at 1:16 PM, Dampsquid said:

Am I right in thinking the thermostat acts like a switch in that when cold, water path is from transmission cooler straight to exhaust manifolds, and when hot, the thermostat blocks that path and instead opens the path from the block, so water now flows out from the block into the exhaust?

No, the water from inside the block that doesn't go past the thermostat instead goes into the exhaust manifolds or gets recirculated.  When the water in the block gets hot, the thermostat opens to allow the hot water to go to the exhaust manifolds; e.g. it does NOT "block that path" of the cold water to the manifolds.

https://www.indmar.com.au/59/indmar-pump-raw-water-hi-flow.jpg

1 hour ago, Dampsquid said:

On the boat, the new pump is moving water from a bucket placed on the floor of the boat through the engine - so success.  But, it's not as much as last year.  So I think there may also be an issue with the circulation pump.  My theory is after the thermostat opens there should be a higher flow rate out the exhaust than compared to the raw pump alone - and I'm not seeing that.

Again, the opening of the thermostat only opens up an addition exit path for the water.  ALL water coming out the exhaust must pass through the impeller beforehand.  The circulation pump circulates the water in the block regardless if it is hot or cold.  It for sure adds motive flow, but not when it is circulating air.  If your problem is with the raw water pump housing making a good seal with the impeller (e.g. drawing in air) the healthy circulation pump won't be able to do its job.

[oldjeep]

On ‎10‎/‎7‎/‎2018 at 12:21 AM, shawndoggy said:

the whole antifreeze from a bucket theory is in general a bad one.  If you really want to fill the block with antifreeze, there's one right way to do it: drain the block, reinstall block drains, remove thermostat housing, fill with antifreeze, reinstall thermostat housing.

Or just dump the antifreeze in via the hoses. No reason to be messing with the thermostat

[Bozboat]

http://www.themalibucrew.com/index.php?/forums/topic/37531-cooling-system-for-dummies/

 

No offense intended, it is a good explanation

[footndale]

1 hour ago, oldjeep said:

Or just dump the antifreeze in via the hoses. No reason to be messing with the thermostat

Which is this hose.