Mag-drive pumps not restarting


Premium Member
I have a couple of mag-drive pumps that will not restart reliably. Anyone know the cause of this? I have cleaned them a couple of times but no luck. I think one is a mag-5 and the other is a mag-7. Nothing appears to be wrong with the impeller. It seems that I saw a post ages ago where hole in the impeller cover (the one that the impeller shaft fits into) gets ever so slightly oval'ed out and causes the impeller to bind up on start-up. Not sure if there is any truth to it or not. Is there a cheap fix? Hate to go throwing $150 worth of pumps in the garbage. About the only thing I can rely on them for now is for mixing salt.


New member
I'm not sure if it's quite the same problem but I just had a mag drive 7 for my skimmer stop working, and seems that the impeller will not spin when the cover is on as if it's binding up, with no visible calcium deposits or anything. I wasn't able to fix mine and reluctantly had to buy a new pump. Not sure what the deal is with these


Dad with Triplets!
I have a couple of mag-7 that over 5 years old. After a year or two mine will do the same thing. Just buy a $12 impeller and the pump is good as new.



Premium Member
Drew is right, the impeller magnets over time will swell due to heat issues and cause the magnet to be out of balance and stick to the inside of the motor. It is a common problem with mag pumps.


New member
I had a mag 12 doing the same thing. I found the impeller assemble rubbed against the cover causing a small groove i sanded the groove smoothe again and that solve the problem.
I think usually its an impeller problem


Premium Member
I had the exact problem that the OP explained, my MAG12 would not restart.

I took it apart & the impeller was perfect ( and magnet & shaft ).

The hole in the volute ( cover ) had been worn out & was an oval shape.

This makes the impeller touch the side of the pump housing & it wont restart reliably.

Buy a new volute.