Raw water pump information

Raw water pump information

Joined: August 25th, 2005, 5:45 am

September 20th, 2005, 5:59 am #1

Hi, that other thread about "The boat is floating again" is getting so long that I thought I'd start a new one.

Our 38' Commander has fresh water cooling, and we have had our port engine heating up more than the starboard. When on a slow cruise, the temperature of the expansion tank for the starboard engine runs about 180 degrees F, while on the port engine it runs about 210 degrees F. By the way, one of the first things we did was put new impellers in the raw water pumps.

We have been slowly going through all parts of the cooling system on the port engine. I had the engine heat exchanger out and opened up -- all is good there. I cleaned up the 2 psi relief valves controlling raw water coming out of the heat exchanger, and they are looking good. We back-flushed the engine oil and transmission coolers -- no evidence of any blockage there. I inspected various parts of the fresh water side -- the fresh water pump looks good, the coolant passages we could see all are clean, the thermostat opens when it should (as tested in a pot of water on the stove), the vee-belts are tight. We have been scratching our heads trying to figure out what the problem is.

The other day we decided to run a raw water pump output test. Using hose we directed the pump output into a 5 gallon bucket and measured the amount of water we got in 30 seconds with the engine at 1500 rpm. Then we did the same test to the starboard engine, with the engine at the same RPM. Turns out the port raw water pump was putting out about 30% less volume!

So we pulled the port raw water pump and looked it over. All seemed good. We decided to take it to a guy we know that is a marine mechanic to have a look at it. He took a little hook and reached up into the pump intake elbow, and pulled out a small handfull of pieces of rubber!

We had previously inspected the pump output passage assuming any broken impeller pieces would lodge there, but it didn't occur to us that they would be stuck in the pump intake side. Apparently someone had shredded an impeller sometime in the past by running it dry, and this mechanic told us that suprisingly often impeller pieces will somehow back up into the intake side of the pump.

Live and learn! Hopefully tomorrow we will get the pump reinstalled and see if we have eliminated or at least reduced our overheating problems.





1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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Paul
Paul

September 20th, 2005, 6:35 pm #2

Good find on the debris, lots of time when one impeller blade lets go, it takes another one with it, and sometimes they all go. WHen only one goes or a part of one goes, the pieces can and do get pushed into the water cooling system, where they end up nobody knows for sure. Most of the time if they make it out of the pump and initial piping, they may get caught somewhere in the system where it really does not matter. You have checked the immediate area around the output side of the pump, which is good, however, you might want to check the discharge side of the system too, because there could be some pieces being held under pressure into that area. I'm not sure if compressed air can be used to retrieve pieces that are lodged way into the system. The good news is, your system has antifreeze around the cylinder bores. On a raw water cooling system (called the "standard cooling system" by Chris Craft, as opposed to the "closed cooling system" you have on your boat) those worn impeller bits would be pushed all the way through the internal parts of the motor and nobody knows (or will ever know) where they end up, nor are those able to be retrieved.

Your oil cooler may have some blockage in it too.



Your reverse gear cooler may have debris in it too, if anything got by the oil cooler. The oil cooler on the 427 may pass particles, but I don't think the transmission cooler design will. You might want to check these for debris.

This could be a major discovery. Let me know if you find anything.

Regards, P
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Joined: August 25th, 2005, 5:45 am

September 21st, 2005, 3:55 am #3

Hi, that other thread about "The boat is floating again" is getting so long that I thought I'd start a new one.

Our 38' Commander has fresh water cooling, and we have had our port engine heating up more than the starboard. When on a slow cruise, the temperature of the expansion tank for the starboard engine runs about 180 degrees F, while on the port engine it runs about 210 degrees F. By the way, one of the first things we did was put new impellers in the raw water pumps.

We have been slowly going through all parts of the cooling system on the port engine. I had the engine heat exchanger out and opened up -- all is good there. I cleaned up the 2 psi relief valves controlling raw water coming out of the heat exchanger, and they are looking good. We back-flushed the engine oil and transmission coolers -- no evidence of any blockage there. I inspected various parts of the fresh water side -- the fresh water pump looks good, the coolant passages we could see all are clean, the thermostat opens when it should (as tested in a pot of water on the stove), the vee-belts are tight. We have been scratching our heads trying to figure out what the problem is.

The other day we decided to run a raw water pump output test. Using hose we directed the pump output into a 5 gallon bucket and measured the amount of water we got in 30 seconds with the engine at 1500 rpm. Then we did the same test to the starboard engine, with the engine at the same RPM. Turns out the port raw water pump was putting out about 30% less volume!

So we pulled the port raw water pump and looked it over. All seemed good. We decided to take it to a guy we know that is a marine mechanic to have a look at it. He took a little hook and reached up into the pump intake elbow, and pulled out a small handfull of pieces of rubber!

We had previously inspected the pump output passage assuming any broken impeller pieces would lodge there, but it didn't occur to us that they would be stuck in the pump intake side. Apparently someone had shredded an impeller sometime in the past by running it dry, and this mechanic told us that suprisingly often impeller pieces will somehow back up into the intake side of the pump.

Live and learn! Hopefully tomorrow we will get the pump reinstalled and see if we have eliminated or at least reduced our overheating problems.





1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
Hi, here is an update on our port engine cooling problem.

But first: Paul, I want to say thanks so much for the good words of advice on this cooling problem you have provided and all your other help too (which has not only been helpful, but has also got us by some really hard spots we were stuck at). You mentioned debris stuck in various parts of the cooling system. Yes, I have been very concerned about the same thing -- that pieces of impeller rubber and other debris could be stuck in the engine oil cooler and/or the transmission oil cooler. Consequently, we recently did a back flush both of those coolers individually with a garden hose (with water at a high 70 psi) and they appeared to flow unrestricted and we got no debris in our catch-bucket. But I was still worried stuff could still be jamed in the passages of those coolers. Additionally, we had the transmission oil cooler off a few weeks ago (when we overhauled the transmission) and the shop checked it out and pressure tested it as OK.

So here is our update as of today: We put the port raw water pump back together after I chiseled out the old lop-sided bearing in the end-plate, and pressed in a new graphite bearing. I also re-surfaced the end-plate on a 6" belt-sander so it is smooth and flat (it had some minor grooving worn into it from the rubber impeller rotation). I lubed everything with silicone grease, stuck the impeller back in and using a new gasket put the pump back together. We then reinstalled it on the port engine and crossed our fingers on both hands as we fired the engine up and waited for it to heat up.

Yahoo! After 30 minutes at 1500 RPM, the expansion tank temperature never exceeded 150 degrees F. Before it was hitting 210 degrees F! So we are thinking that we have fixed the overheating problem on the port engine.

And also today we traced all the wiring on the port engine alternator which was not putting out any charging power before. We found a broken wire, fixed it, and now the alternator is working. On a fast idle the battery voltage goes from 12.6 volts up to 14.4 volts.

I think we are just about FINALLY ready to be able to start the engines, cruise for an hour, and have confidence that we can make it back to the dock under power. We are both very excited!!!!! Gosh, it will sure be good to get out of the bilge and start working above-deck.

Best wishes.....



1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
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P
P

September 21st, 2005, 5:28 am #4

thanks for the good words, hope all the back breaking work in the bilge pays off for you. Lots of us with the older boats, especially those of us who bought "project boats" know exactly what you are going through. One thing about it, having been there and done it, then you'll be able to diagnose and fix just about anything. Hey, the cup is half full, right??

All the best, Paul
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Curt in PDX
Curt in PDX

September 21st, 2005, 8:40 am #5

Yeah, I feel like we will be able to fix about anything after all we and been through. We are definitely doing the "hard stuff" first. Other than the engines and transmissions, pretty much everything else on the boat is reasonably straight-forward (even though some of it will take quite a bit of time).

You know, I think what is most satisfying about all this is that we are able to totally understand the engines, transmissions, and controls -- unlike when I look under the hood of my car (engine hidden with plastic covers, computer controls everwhere, hardly anything I recognize). This boat was built in the same year I got out of college, and I worked on many car engines during that era. I am remembering more and more about things I used to know but forgot over the years about 60's engines and carburators and engine wiring. In fact, when I popped the top off the Carter AFB carburetor on these 427's, it looked so familiar that I got a smile on my face -- I had rebuilt several of these 40 years ago.

So unless something expensive goes totally south on us (like a rod going through the side of a block), we are both having fun (with momentary setbacks) and using old and almost forgotten knowledge again. We are also getting to use a lot of tools that have been sitting in our individual tool boxes for years mostly unused.

Some upcoming significant projects:

Redo battery shore power charging system. I have already obtained the parts to do this: new microprocessor controlled 60 amp three stage charger, West Maring battery combiner, Xantrex Link 20 battery monitor. This will be a fairly straight forward job now that we have 264 pounds of new Trojan deep cycle batteries aboard with all new cabling. Tonight I built battery trays to hold the new batteries.

The total 120v AC system on the boat is wired with solid (not stranded) Romex, and the two fuse/breaker boxes are junk. Today I pulled enough paneling to find things like several unsecured Romex cables laying directly on the top of the fuel tanks! I will be redoing virtually 100% of the 120v system including the breaker boxes. Whoever wired the 120v stuff on this boat really didn't have a clue about 120v wiring.

Getting engine instruments working -- no instruments are currently working except the temporary set of electronic tachs I installed. We need to get water temp and oil pressure gauges working. There are dozens of loose and/or broken wires around the engines and instrument panels, and I think careful tracing and reconnecting wires may let some or most of the instruments come back to life.

Replacing rear cockpit deck and supporting structrual members. Yesterday we pulled out the hoses that pipe the main deck drains down and out through the hull. These two 2" hoses were original (38 years old), were rotten, and literally looked like Swiss cheese -- almost all rain water hitting the front half of the boat was running directly onto the wood structure supporting the rear decks. We knew about this problem when we bought the boat. The fix will take some time and effort, but will not be very complex work (at least I don't think it will). We probably won't start this project until next summer when the weather will be warm and dry.

Enough for now.

Later, Curt...

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Paul
Paul

September 21st, 2005, 12:14 pm #6

Man you're up early (I'm here at the office preparing for a brutal day of meetings, sure wish I was on a boat working on something.....anything would do!)

Regarding instruments, I'd think oil pressure is the big one right now, to judge how the engines are performing. You have a digital temp gauge so you can cover that manually if need be. Those old sending units may be junk (they sell two kinds, one for a single install and another for a dual install, be sure to get the proper one if you need new ones. Spinning the fuses may be all that's needed for some of the instruments and systems, never know.

Regards and good luck on your continuing project, like I said, I'd sure rather be on a boat right now than preparing to go into a room full of swarming hornets from out of town!

Paul
Last edited by FEfinaticP on September 21st, 2005, 12:29 pm, edited 1 time in total.
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Joined: July 15th, 2005, 8:09 pm

September 21st, 2005, 7:12 pm #7

Yeah, I feel like we will be able to fix about anything after all we and been through. We are definitely doing the "hard stuff" first. Other than the engines and transmissions, pretty much everything else on the boat is reasonably straight-forward (even though some of it will take quite a bit of time).

You know, I think what is most satisfying about all this is that we are able to totally understand the engines, transmissions, and controls -- unlike when I look under the hood of my car (engine hidden with plastic covers, computer controls everwhere, hardly anything I recognize). This boat was built in the same year I got out of college, and I worked on many car engines during that era. I am remembering more and more about things I used to know but forgot over the years about 60's engines and carburators and engine wiring. In fact, when I popped the top off the Carter AFB carburetor on these 427's, it looked so familiar that I got a smile on my face -- I had rebuilt several of these 40 years ago.

So unless something expensive goes totally south on us (like a rod going through the side of a block), we are both having fun (with momentary setbacks) and using old and almost forgotten knowledge again. We are also getting to use a lot of tools that have been sitting in our individual tool boxes for years mostly unused.

Some upcoming significant projects:

Redo battery shore power charging system. I have already obtained the parts to do this: new microprocessor controlled 60 amp three stage charger, West Maring battery combiner, Xantrex Link 20 battery monitor. This will be a fairly straight forward job now that we have 264 pounds of new Trojan deep cycle batteries aboard with all new cabling. Tonight I built battery trays to hold the new batteries.

The total 120v AC system on the boat is wired with solid (not stranded) Romex, and the two fuse/breaker boxes are junk. Today I pulled enough paneling to find things like several unsecured Romex cables laying directly on the top of the fuel tanks! I will be redoing virtually 100% of the 120v system including the breaker boxes. Whoever wired the 120v stuff on this boat really didn't have a clue about 120v wiring.

Getting engine instruments working -- no instruments are currently working except the temporary set of electronic tachs I installed. We need to get water temp and oil pressure gauges working. There are dozens of loose and/or broken wires around the engines and instrument panels, and I think careful tracing and reconnecting wires may let some or most of the instruments come back to life.

Replacing rear cockpit deck and supporting structrual members. Yesterday we pulled out the hoses that pipe the main deck drains down and out through the hull. These two 2" hoses were original (38 years old), were rotten, and literally looked like Swiss cheese -- almost all rain water hitting the front half of the boat was running directly onto the wood structure supporting the rear decks. We knew about this problem when we bought the boat. The fix will take some time and effort, but will not be very complex work (at least I don't think it will). We probably won't start this project until next summer when the weather will be warm and dry.

Enough for now.

Later, Curt...




A painted motor really doesnt' run any better than a non-painted motor, but it sure shows pride of ownership, and it's a signal to all that things have been looked over and taken care of. Everyone's going to want to see those motors, and it sure is a lot more comfort working on a motor that presents itself well, rather than one that shows the lack of attention it's received over the years.

Nice job! You'll want to show these off to everyone who comes aboard. I hope you keep a nice photo album too, because the photos you've shared here are great.

regards, Paul
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Curt in PDX
Curt in PDX

September 21st, 2005, 7:13 pm #8

Man you're up early (I'm here at the office preparing for a brutal day of meetings, sure wish I was on a boat working on something.....anything would do!)

Regarding instruments, I'd think oil pressure is the big one right now, to judge how the engines are performing. You have a digital temp gauge so you can cover that manually if need be. Those old sending units may be junk (they sell two kinds, one for a single install and another for a dual install, be sure to get the proper one if you need new ones. Spinning the fuses may be all that's needed for some of the instruments and systems, never know.

Regards and good luck on your continuing project, like I said, I'd sure rather be on a boat right now than preparing to go into a room full of swarming hornets from out of town!

Paul
You said: "I'd sure rather be on a boat right now than preparing to go into a room full of swarming hornets from out of town!"

Did that for years until I retired - meetings, meetings, more meetings. Presentations, sales pitches, briefings, finance and budget reviews, questions and answers. Hundreds of meetings full of people who all liked to pontificate and hear themselves talk.

Thinking back, my worst day on this boat was better than nearly any day in the office! Glad to have moved on.

Well, I gotta head for the boat and get started on the 12v charging system.
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Curt in PDX
Curt in PDX

September 21st, 2005, 7:19 pm #9





A painted motor really doesnt' run any better than a non-painted motor, but it sure shows pride of ownership, and it's a signal to all that things have been looked over and taken care of. Everyone's going to want to see those motors, and it sure is a lot more comfort working on a motor that presents itself well, rather than one that shows the lack of attention it's received over the years.

Nice job! You'll want to show these off to everyone who comes aboard. I hope you keep a nice photo album too, because the photos you've shared here are great.

regards, Paul
...that a nice clean engine sure presents itself better than a dirty greasy one. And you know what? I almost think a freshly painted engine runs better. Well, it sure seems like it anyway, huh?

I gotta get after cleaning up and painting the filty gen-set next. After that, some fresh gray deck and porch paint on the decks and sides should make it nearly a show-place down there. I may have to put in glass panels in the engine room cover hatches so people can look down there!

Best wishes....
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P
P

September 21st, 2005, 11:22 pm #10

it would be a lot more useful there, and it wouldn't be consuming gas from the dead weight I carry around all the time. With an inverter, we really have no need for a generator.

Todd Heinrich takes 500 and 700 mile trips in his 38 and he doesn't have a generator. Why do I need one??

P
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