pump locks up

My 640gph pump keeps locking up. It has no problem running out of water or in freshwater, but after 10-30 secs in saltwater it just locks up. You can feel the motor trying to turn the impeller, but it won't move. I tried cleaning the whole thing out. Is there anything else to do?

 

run it in vinegar water over night. mix vinegar 1:8 water. Rinse and let dry. Works for me.

 

That would be a plain vinegar, correct?

 

It locks up, even in the vinegar. It's been in there for about 1/2 hour.

The impeller sounds like it's unevenly rotating, and hitting something, which gets progressively worse (louder hits) as the pump runs for longer, before it stops.

Should I be concerned, or do something else?

 

is the bottom of the shaft broken off?

 

Hey buddy. First what kind of pump & second never run a pump dry, the water acts as a lubricate. I had a Mag 7 that had a similar problem, the result was a snapped shaft. I replaced the impeller assy & the front housing because it wore the inner housing.

I would try to take the pump apart, to see is first if there is something broken or a piece of something that got sucked up. Then inspect the inner housing to make sure there is no wear.

 

Don't run it in the vinegar, just soak it in there to remove any lime deposits on it. Then the next day take it out and clean it inside the housing.

It sounds to me like its heating up and the housing is warping and impeller mag is hanging up.

But the problem with that theory is it should do it no matter what water its in...that is unless the fresh water is colder that the salt water.

 

I don't think so, but I'll check it now.

 

lol.. great minds think alike.. ;D

 

I took out the impeller a few times already. Nothing seemed out of the ordinary with it. Small amounts of calcium carbonate buildup on it.

I only ran it dry for about a second at a time, before submerging it. I figured out I can get it to start rotating by taking off the snap-down piece, which holds down the piece holding the front bearing of the impeller.