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Schooner Captain
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Discussion Starter · #1 ·
So I am down to the last of the projects for the generator, and I hate to say but the harbor freight pump it came with is just junk.
I would like a good one.
It will have to suck about 3' of head, and start dry many times.

The one it has not uses a hard plastic impeller, and it has plastic leafs inside that come out. It works fine, then randomly loses suction, and goes dry. Not good when under load.

The two options I have are

Option 1, find a good 12V pump
Option 2, mount a pump on the motor.
Nextgen and phasor both mount on the motor now, and I have a pulley, but would rather not.
 

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One of None
Hunter 34
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9,026 Posts
Pump needs to be below water line but you will have trouble finding a 12 volt motor for continuous operation and longevity you need. 120 volt motors are way more dependable Good impellers do not lose prime, but a ck valve will work IF you have a good strainer. All that pretty much tells me go with the belt driven pump!
 

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Schooner Captain
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2,199 Posts
Discussion Starter · #5 ·

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Schooner Captain
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2,199 Posts
Discussion Starter · #6 ·
Pump needs to be below water line but you will have trouble finding a 12 volt motor for continuous operation and longevity you need. 120 volt motors are way more dependable Good impellers do not lose prime, but a ck valve will work IF you have a good strainer. All that pretty much tells me go with the belt driven pump!
Good points. If I did a 120 volt I actually have a really good one I could use, centrifugal thou, so it would have to be under the waterline, or like you said, have a check valve. I could also use the March Mini Pump in 12 volts.
 

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Master Mariner
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9,415 Posts
You cannot use a check valve with a centrifugal pump.
I have been using the little giant magnetic drive pumps, mounted below the water line, for some 30 years on AC systems (continuous operation for long periods in summer) without problems, but you will need to find out if that or the March will supply the proper gpm for a generator cooling system.
Are you raw water cooling this engine? Are you trying to convert a radiator cooled unit to marine use?
 

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Schooner Captain
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2,199 Posts
Discussion Starter · #9 ·
Why does it have to run 24/7? I have one of these also running on 115VAC that runs my AC/Heat pump system, and it has held up for 2 years now.

Gary :cool:
its more of a rating then an actual use.
I may run the generator for 4-8 hours if we are in a nasty hot part of the world.
You having used one on your AC system is a testament to how good they are thou.
 

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Schooner Captain
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2,199 Posts
Discussion Starter · #10 ·
You cannot use a check valve with a centrifugal pump.
I have been using the little giant magnetic drive pumps, mounted below the water line, for some 30 years on AC systems (continuous operation for long periods in summer) without problems, but you will need to find out if that or the March will supply the proper gpm for a generator cooling system.
Are you raw water cooling this engine? Are you trying to convert a radiator cooled unit to marine use?
The unit is a phasor 3.5KW.
Requires 3GPM.
 

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I've never seen a marine generator that didn't have a mechanically driven or belt driven water pump.

If I was going to use an external electric pump, I would want two aboard, just like one has two impellers, belts, etc. The impellers and belts are much cheaper, however.
 

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Schooner Captain
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2,199 Posts
Discussion Starter · #12 · (Edited)
I've never seen a marine generator that didn't have a mechanically driven or belt driven water pump.
Here you go.


If I was going to use an external electric pump, I would want two aboard, just like one has two impellers, belts, etc. The impellers and belts are much cheaper, however.
Your right, I need two.
I can add an engine mounted one, but they are expensive, and would it want to suck water 4' from the waterline? I would be out $400 before it was on and mounted.
 

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Fascinating. I wonder what advantage they're going for to not have an engine driven pump.

Well, it is a generator, so there's no reason you can't have a 110v pump. We have some big monster in the bilge that pumps water to our AC units, but I don't know the brand. It's the size of a bread box. Run continuously (when AC is on).
 

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Schooner Captain
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Discussion Starter · #16 ·
Fascinating. I wonder what advantage they're going for to not have an engine driven pump.

Well, it is a generator, so there's no reason you can't have a 110v pump. We have some big monster in the bilge that pumps water to our AC units, but I don't know the brand. It's the size of a bread box. Run continuously (when AC is on).
I have one of those too, started with a small one, was too small, now we have a big one.
I need to make it more neat.


3GPM is the smallest one they make, I guess I could mount it below the waterline.

 

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Super Moderator
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6,855 Posts
Wet exhaust
How are you going to not hydrolock if you have a waterlift or any up hill run with the exhaust exit.. ? A belt or gear driven pump works at the RPM of the engine and balances wet exhaust water flow to engine RPM & exhaust gas pressure.. If going 12V (or non engine RPM driven) you will likely want a delay on start and a pre-shut off on turn off....

I had a customer hydrolock his engine when he used his blaster wash down pump temporarily when he lost his impeller and did not have a spare...
 

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Schooner Captain
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2,199 Posts
Discussion Starter · #18 ·
With the generator it runs at a set rpm.
I would never turn it on before, but I think I would put it on a switch to shut it off before I shut off the generator. The generator itself sits 3' above the waterline. The only uphill is the loop in the exhaust.
Actually I think this is solved, I think I will keep my eyes open for a small one at sailors exchange. a 120 volt 3.5 GPM march pump. Will be a jerk to work on, below the waterline, but should work awesome.

Thanks everyone!
 

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According the web page for that generator, it comes with a "belt driven impeller type raw water pump".
With all due respect, putting an electrical pump controlled by a switch that must be manually activated in order to not destroy the unit is probably one of the most bubbatized fixes I've seen in a while.
 
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