Post edited 4:52 pm – August 30, 2009 by Steve Pooler

4000 said:

Post edited 11:29 am – August 30, 2009 by 4000

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Hi,

The March Pump is model “LC-3CP-MD”.

After discovering that there was no waterflow, I pulled the outlet hose from the impeller housing to see if the impeller was spinning. The impeller didn't spin, so I took off the entire impeller housing to see if the motor itself would spin. The motor spun freely to my hand and also spun at a high rate when I turned on the compressor.

After reading the advice given here, I purchased a new “wet end”. (The entire impeller unit from the cover to the rear housing) After sweating it in the bilge for a few hours, I went inside, grabbed a cold beer and pressed the “ON” button only to discover . . . No water flow!

Is there something else I should look for before I commit to a new pump? By the way  . . .  I didn't replace the “cover” of the impeller assembly and chose to keep the old one. It was darn frozen on to the pipe that leads to the strainer. As far as I could tell, it didn't look like it impeded the movement of the impeller at all. Could that be a problem? Do motors get weak enough so that although it spins on its own, can't spin the impeller?

When you pulled the outlet hose…Did water come out with the thru hull open ?

If not…This may be what caused the first pump head to fail…Loss of water supply, or Air lock…

I would suggest removing that hose again with the thru hull open to let out any air (You should get solid clear water) and then try again…

Do you hear the pump run now that you have it all assembled ?

To answer the second question…No…Not usually, although I have found a few weak magnets in the past causing the impeller to not spin under a load (with water in the head) It is very rare though…

Steve~

4000 said:

Steve,

Thanks for the quick reply. OK, I'll give that a twirl. I had thought that since everything was below water level, water would just naurally fill the entire assembly. Am I correct in assuming that the “manual prime” you described is a required step for installations?

Up North, we are probably only a few weeks from calling our AC's, “heaters”. . .

No…Not really…If everything was installed in a constant uphill from thru hull, to strainer, to pump, then unit, with NO dips or loops it should prime itself (providing all this is under the waterline)

Any place that can trap air…Will…Which will also mandate the manual bleed procedure…More times than I'm sure you would care to do.

This could also have been the cause of your failure…

Steve~ 

Post edited 1:47 am – September 10, 2009 by Steve Pooler

4000 said:

Just as a follow up. . .

Tried all the steps and I think the motor is bad. The motor will STILL spin . . . but the impeller spun for a few seconds and then locked up. All this with the water outlet side completely off so that I could peak into the impeller somewhat. (Difficult to do with all the gushing water)

Anyhow, I just ordered a new pump. I'll let you know how that goes . ..

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The new pump should cure the problem for sure but…The points you say…”but the impeller spun for a few seconds and then locked up…”Difficult to do with all the gushing water”

The gushing water is a good thing…Maybe it didn't have that when it failed ???…

It makes me think that the pump head itself had a problem…Maybe a lack of water supply at one time…

4000…It's not easy to see, but the impeller will melt itself into the housing and then cool….Leaving a rough surface for it to ride on the next time it starts….It may make a few turns, but soon after it will quit spinning (and also quit pumping water) because of the rough surface it left when hot last time….

I'm not saying this is the case in your situation…But I am saying I've seen it often.  

What I'm saying is…The motor may make a few revolutions after the impeller is stuck…It's not direct drive…But “Magnetically Coupled”

It's rare that the motor quits in this way with no horsepower…It usually just Quits.

Steve~

Post edited 4:13 pm – September 11, 2009 by Steve Pooler

Maybe what I've not gotten across is that you need to remove the white pump head completely from the motor…

You will then see the motor magnet on the motor shaft…

Turn on power to the motor…If it does not start & run…Rotate it with your hand to see if it is stuck (sometimes they do) and if it is/was but now runs after rotating it by hand…It likely got water into that part of the housing from a leaky o-ring (and the pump submerged) or the motor heated up from clogged cooing tubes (little stainless tubes connected to the head)

If the above is true (motor was stuck) then yes…You should get a complete pump…But the old one could be used for a spare…after blowing out the cooling tube & lubricating the bearing with some kind of liquid oil poured into the housing (with the head off) and the motor stood on end for a bit.

If the motor takes off & runs without the head connected…and no help from you…

Then the problem is in the head which can be replaced…And this pump (or the new one) can be used as a spare or for other purposes such as acid flushing the system (submersed in a bucket) or a standby bilge/tank pump…They are good pumps to have around 

Steve~