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Discussion Starter #1
I have a Universal 5411, no heat exchange. My problem is slightly different from the other hot threads.

When I start the engine, and keep it at low revs, no water comes out the exhaust, and she goes over 180 degrees. But, if I rev up the RPMs, she will pump SOME water and stabilize at 162 degrees. 12 degrees too hot (if the gauge is correct).

I can't determine if;
1) I have an air leak
2) impeller is worn.
3) Thermostat needs replaced (NO water until 160 degrees)
4) Partial blockage some where.

Would anyone care to give me a start?
 

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How old is your impeller? Does it have all of it's vanes?

It is the hart of your cooling system.
 

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I would suspect you have wear in raw water pump which has opened up the clearances and prevents the pump from picking up a prime. Exact same thing happened to the pump on my 5411. Remove the pump cover and I bet you will see circular grooves. If you file the cover smooth and replace it, the pump will probably work much better.

Note that the 5411 does not put a lot of water into the exhaust since it recircs most of it. The key thing to watch is the temperature. Should ideally be 135 to 150, but 160 is OK.
 

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Discussion Starter #5
Many thanks to the responses.

A visual on the impeller looks fine. I don't see any grooves. The thin seal on the cap looks fine.

I'm going to start taking things apart this weekend, but before I do, I'm going to hang a bucket under the exhaust and capture 1 minute of running full open and measure the amount of water. I have no idea how much there should be.

Has anyone ever done that measurement?

I didn't understand the recirculation comment. Why run hot water back through the engine????
 

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I didn't understand the recirculation comment. Why run hot water back through the engine????
The 5411 is raw water cooled. When you first start up, the thermostat recirculates virtually all the water back to the pump suction to quickly increase the temperature to operating. AS the temperature approaches 140, the thermostat partially closes and starts sending water out the exhaust, but just enough to maintain the water temperature. See the drawing in the engine manual. If you don't have one, you can download one at International Catalina 30 Association.
 

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Discussion Starter #7
UPDATE
I polished the cap on the water pump with fine sandpaper. It fixed the priming question.

Next, I'm going to pull the thermostat and put it in a pan of water being heated. Add a meat thermometer and see when it opens. If that works, it should answer the question of temp gauge being off or the thermostat is in error. I hope. (Memories from owning a 1949 Ford) HA!

As for the water flow. I warmed up the 5411, ran the throttle wide open for exactly 60 seconds and captured the water from the exhaust in a bucket.
It measured exactly 48 fl. ounces. I've noticed other's post inquiring about how much water should be exhausted. That's my measure.
 

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No! Note my post #6. The 5411 is raw-water cooled, not fresh-water cooled like the 5432.
I did note that, but it was as close of a reference to flow volume I could find for that engine. I would believe the water pump would push the same volume through a heat exchange as as it would the engine block for a raw water cooled engine.
 

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Maybe it would be worth checking your raw water strainer for an air leak.

I had a similar problem recently which was not resolved by replacing the impeller, but was cured by putting in a new strainer. The old one was leaking air so that the impeller was pulling air into the system, and prevented proper suction at the through hull intake. Result - No water from the exhaust.
 

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I did note that, but it was as close of a reference to flow volume I could find for that engine. I would believe the water pump would push the same volume thorough a heat exchange as as it would the engine block for a raw water cooled engine.
Same volume goes through the block, but only a fraction goes into the exhaust as most is recirculated by the thermostat back to the pump suction.
 

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Jim, you are more familiar with the engine than I. The OP said he warmed up the engine and ran it under full power for 1 min and only got a quart and 1/2 of cooling water out of the exhaust.

Sounds like the water flow is restricted to Me. Because he says the pump looks good. Could be the thermostat, but either way I would expect more water out of the exhaust at full temp and full throttle.
 

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Jim, you are more familiar with the engine than I. The OP said he warmed up the engine and ran it under full power for 1 min and only got a quart and 1/2 of cooling water out of the exhaust.

Sounds like the water flow is restricted to Me. Because he says the pump looks good. Could be the thermostat, but either way I would expect more water out of the exhaust at full temp and full throttle.
Your right about my knowledge of the 5411 - I've lived with one for 20 years. Because of the way the thermostat controls water temp (by recirculation) the volume exhausted varies greatly - from almost nothing at startup to quite a bit when motoring at full power in warm water. At idle (which I am sure is when the flow was checked) it will be fairly low even with a warmed up engine. The reading on the water temperature gauge is the most important thing to watch.
 

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Bud, Ignore the amount of water flow into the exhaust as long as the water temp is OK.
 
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