No water coming out... Problem?

[Rbyham]

I am early model rwc no thermostat manual recirculating valve setup. I opened the recirculating yesterday in an effort to increase engine temp because I wanted to confirm gauge was working. Sure enough temp went from 140 to 17p in about a minute. Gauge confirmed. During this test I also monitored the exhaust. U was surprised to see no water coming out. Zero. Just steam/smoke. So I quick closed recirculating line and everything returned to normal... temp (140ish) and exhaust water flow was good. Is this normal or should I be concerned? I was surprised that opening the recirculating would completely stop flow out the back. Seems it could be dangerous to let exhaust system overheat...

[ndutton]

It sounds to me like the early model cooling system is doing what it's designed to do, reduce precious cooling water to the exhaust in favor of warming up the engine more quickly. I know there are very knowledgeable members who prefer this system over the late model but cutting down - or off - water to the exhaust gives me the willies. By design it also reduces - or stops - flow through the raw water pump regardless of RPM. Uber willies.

At a minimum I'd caution those with early model systems to avoid a Vetus waterlift muffler. They are known to be the least tolerant of elevated temps even for the shortest of times.

[67c&ccorv]

Originally Posted by Rbyham

I am early model rwc no thermostat manual recirculating valve setup. I opened the recirculating yesterday in an effort to increase engine temp because I wanted to confirm gauge was working. Sure enough temp went from 140 to 17p in about a minute. Gauge confirmed. During this test I also monitored the exhaust. U was surprised to see no water coming out. Zero. Just steam/smoke. So I quick closed recirculating line and everything returned to normal... temp (140ish) and exhaust water flow was good. Is this normal or should I be concerned? I was surprised that opening the recirculating would completely stop flow out the back. Seems it could be dangerous to let exhaust system overheat...

That's how the early model system with the Doyle thermostat works.

[hanleyclifford]

Sounds like you could have a partially clogged discharge fitting on the manifold. When you open the bypass the preferential flow is almost complete to the exclusion of the manifold discharge.

[Rbyham]

Had a quick sail this morning. Had to get off water by 9:30 to beat 90+ temps... ☺ gonna be a warm week in Charleston
Anyway. Ran engine hard about 20 minutes. Temp stayed at bottom end {130} of gauge. But I know it is working from yesterday test. My question is should I crack open the bypass to bring temp up a bit? Isn't 130 a bit cool for an early model RWC? What would ideal temp be? I can probably dial it in pretty close...

[edwardc]

For raw water cooling in saltwater, 140-150 is about right. Above 160, the salt starts to precipate out and clog the cooling system.

[tomsailmaker]

I think Hanley is right there should be some water coming through the exhaust. You have no thermostat installed so some water should be coming through the system. I am running a DOYLE system and it is great. I have set mine up to run through a 150 degree thermostat on one side and the other side runs through a 6gal water heater,then out to valves to direct the water to either the water pump or into the exhaust mixer. Adjusting the flow through the valves gives me good control over the temp that I am running and how hot my water heater is running. If I direct the water to recirculate there is some flow past the thermostat and I bring the temp right up to were I want to run and adjust from there to meet the conditions

[Marian Claire]

Rbyham. Does your system look like the second diagram. Note the fine print about the valve location. "in the return line" AKA recirculation loop. http://www.moyermarine.com/forums/showthread.php?t=4267
I think we need to clarify the terms "bypass" and "recirculate". To me they are two different set ups and do completely different things.
I would like to know what type of valve you have and exactly where it is located. A regular valve in the return line/recirculation loop should not shut off all the water to the exhaust, wet/dry connection. In theory if the valve in the return line/recirculation loop is 100% open the volume of water going to the wet/dry is cut by 50%.
I have yet to find an "original" diagram for the early system. The diagram linked to is one that I helped develop. If it is incorrect please let me know.
To answer your last question. If set up like the diagram. Yes.
Dan S/V Marian Claire

[Marian Claire]

Originally Posted by ndutton

It sounds to me like the early model cooling system is doing what it's designed to do, reduce precious cooling water to the exhaust in favor of warming up the engine more quickly. I know there are very knowledgeable members who prefer this system over the late model but cutting down - or off - water to the exhaust gives me the willies. By design it also reduces - or stops - flow through the raw water pump regardless of RPM. Uber willies.

At a minimum I'd caution those with early model systems to avoid a Vetus waterlift muffler. They are known to be the least tolerant of elevated temps even for the shortest of times.

My understanding is that the OP has the early system with not T-stat. I can agree that some water, up to 50% if all hoses and fitting are equal, can be diverted away from the wet/dry connection and the rest of the exhaust system down stream.
But I can not see how there is anything but 100% flow thru the RW pump and hence the engine and manifold. The RW intake is never restricted in any way. As the valve in the recirculation loop is open the RW pump has two sources to draw from.
Again if the diagram is wrong let me know.
Dan S/V Marian Claire

[ndutton]

I forgot the recirc went through the pump, thanks. The big issue I have is reduced water to cool the exhaust.

[Rbyham]

Thanks folks... this is all a learning process for me. I believe my setup is very close to the second pic in the link from Marion. I have inserted a picture here of what I think are key parts. The manual valve opens a line that goes down to connect to the line coming from the thru-hull to the water pump. So if I open the manual valve I am feeding hot water from the engine back to the intake...

[tomsailmaker]

Neil My concern about the DOYLE system is the temp of the water pump,over heating the grease cup. With regards to flow through the RWP our early warning system will alert you to that,and don't we all have one of them by now??. RBYHAM should consider reversing the flow through the manifold, see threads on this. Along the same lines I am considering "T" off the "by pass" ahead of my water heater to my sink to have "hot salt water"to use for ??,any thoughts on this??. I have the unique ability to make the simplest things complicated.

[Marian Claire]

Rbyham: Your set up looks correct. Same as what I ran for a year or so before converting to FWC. I do not know if it is my imagination but that line, return line/recirculation loop, looks giant. Is the line out the other side of the T-stat housing the same? Just thinking of the path of least resistance as to why you had no flow to the wet/dry connection when you opened the recirculation loop valve. Have you tried just opening it a small amount?
Dan S/V Marian Claire

[hanleyclifford]

Originally Posted by Marian Claire

Rbyham: Your set up looks correct. Same as what I ran for a year or so before converting to FWC. I do not know if it is my imagination but that line, return line/recirculation loop, looks giant. Is the line out the other side of the T-stat housing the same? Just thinking of the path of least resistance as to why you had no flow to the wet/dry connection when you opened the recirculation loop valve. Have you tried just opening it a small amount?
Dan S/V Marian Claire

Exactly. The bypass loop should be smaller than the rest of the system. I use a 1/2" hose for the bypass, 5/8" for the rest of the system. The preference thru that bypass in the photo should just about preclude any water getting thru to the exhaust system unless the bypass is closed solid.

[Rbyham]

The bypass hose is exactly the same size as that going to the exhaust. This discussion makes me think I should insert a reducer and drop down in hose size. Interestingly as the bypass/recirc hose connects to the rw intake that hose is smaller as it goes to the pump...

[hanleyclifford]

Originally Posted by Rbyham

The bypass hose is exactly the same size as that going to the exhaust. This discussion makes me think I should insert a reducer and drop down in hose size. Interestingly as the bypass/recirc hose connects to the rw intake that hose is smaller as it goes to the pump...

The pump has 3/8" NPT input and output. There is no point in going any larger on the discharge side than 5/8" hose. You can buy brass barbs for 5/8" hose with 3/8" NPT threads on the other end and this is optimal on the discharge side. The intake side from the seacock or strainer can and probably should be larger. Right now you are making the pump pull thru a small hose and discharge into a bigger one; you are losing pressure on the discharge side big time. That is why it is so easy for the water to "prefer" the bypass.

[67c&ccorv]

Frankly - I think you have an abomination in place of a perfectly good early model RWC system with the Doyle thermostat bypass controlled loop.

If it was my boat I would rip out all of the that bypass nonsense controlled by the ball valve (installed no doubt because some PO couldn't find the appropriate Doyle thermostat - or thought the price of one was too high) and go back to the original system.

[Rbyham]

Abomination? Ouch! ☺ Just as frankly here I must confess having no knowledge of what the Doyle even looks like. In my inexperience I even at times wondered if this is not what I had. I shall have to look for pictures though it is unlikely I will pursue a potentially expensive change for an engine that never misses a beat unless you count running year around at 140 with the ball valve never being touched a problem. ☺ Anyone point me to a Doyle pic?

[Marian Claire]

Rbyham: From what I can see you do have the Dole T-stat housing. http://www.moyermarine.com/cgi-bin/s...rebuilder.html
Scroll down and you will see the part from MMI.
http://www.moyermarine.com//forums/a...pictureid=1102
This is a pic of my old Dole housing.
If I understand the history correctly the early A-4 did not have a T-stat at all. It used the recirculation loop with valve to control temp. The Dole housing and T-stat was an "upgrade"/option. As you, I and some others have found the original set up works just fine.
I employ the recirculation loop with valve on my early model FWC cooled A-4. If you ever change to FWC I will be happy to provide info on the set up.
Dan S/V Marian Claire

[67c&ccorv]

Originally Posted by Rbyham

Abomination? Ouch! ☺ Just as frankly here I must confess having no knowledge of what the Doyle even looks like. In my inexperience I even at times wondered if this is not what I had. I shall have to look for pictures though it is unlikely I will pursue a potentially expensive change for an engine that never misses a beat unless you count running year around at 140 with the ball valve never being touched a problem. ☺ Anyone point me to a Doyle pic?

Sorry - I should try and be less frank at times...but IMO the original Doyle system was a very nice setup on early model engines.



I agree with NeilD that until engine cooling water reaches the 140 degree level there is a "chance" that exhaust system components downstream may overheat...which is why I don't use the Vetus plastic system in my vessel.

[ndutton]

It's a puzzlement to me why, in the big picture, the early model RWC Dole system is preferred by so many over the late model system. Very knowledgeable members including Dave Neptune and if I recall correctly even Don are fans of the Dole system. Indigo's aftermarket thermostat system followed the early model design but again IIRC - and sometimes I don't - they modified the original concept to deal with reduced exhaust cooling water.

It's a pretty strong indication however that the Universal engineers felt the late model system was better. I can't imagine them modifying the cooling system to an inferior design when they went from the early model engine to the late model. I think we can all agree that with very few exceptions they were on their game when it came to design and engineering.

For me, the liability of reduced cooling water, even temporarily, to the exhaust outweighs any benefit of quicker warm-up.