Question on Livewell Aerator Pump replacement – Johnson 750 gal pump cartridge

I went to use my livewell last week in 2015 Alumacraft Trophy and it was blowing my breaker fuse. I ended up taking the Johnson 750 Cartridge out and tried turning the impellor. There was some initial resistance and it spun ok. I put back in and it seemed to work ok for most of the day. Then it started making some louder noises. I ordered a new cartridge and tried replacing it last night. I reconnected the wires and turned it on in my driveway. The impellor spun freely prior to installing. After running for about 15 seconds, it was making a fair amount of noise and then blew my breaker again. I removed the cartridge again and now the impellor seems froze up. I ordered another new one from Amazon and will return this one. Did I do something wrong by trying to run it when out of the water? Or was I just unlucky and got a bad pump? Thanks for any suggestions you can provide?

It is bad to run them out of water but surprised that 15 seconds burned it up.

Check to make sure there is no debris or obvious damage in the cartridge mount.

But yeah 15 seconds should not have burnt it up. They aren’t like an outboard impeller that uses water for lubrication. It typically takes a while for the bearing surfaces to heat up enough to cause damage. Next one hook it up and run it in your hand, see what noise it makes then shut it off and install and run it again. If it then makes bad noises I’d say the cartridge mount is damaged in some way or there is something in it that is causing you issues.

I had this same issue with one of these pumps earlier this year. I was replacing an old Mayfair one with a Johnson one I bought as well. It would work in my hand but I put it in the housing and it blew the fuse every time. It did it in both housing for front and rear wells, so I scratched my head. I finally gave up, thinking I got a bad one as well and sent it back. Put the pump from front one into the back well and put off the issue, so I’m interested to hear who figures out the problem.

Have you called Johnson/SPX yet?

https://www.spxflow.com/johnson-pump-marine/support/

HRG

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My auto pump started acting up on my new Skeeter, and was not shutting off after coming on at times. One time after leaving my boat at my cottage, there was a couple days of hard rain there about three days before I returned, and I had forgotten to leave the drain plug open before leaving. Needless to say, when I returned 3 days later, I could hear something running in the boat, it was the auto bilge pump that was stuck on. Had been running for days. Pump still worked, but didn’t pump very well after that. Dealer replaced the pumps after that, and haven’t had a problem since. 15 seconds running dry is nothing to worry about unless Johnson pumps are made differently.

Got the replacement pump cartridge today. Plugged it in and let it run briefly before putting it in the housing. Turned it on briefly again and it sounded ok. I also reached in the housing to see if there was anything that would interfere with the impellor and nothing stood out. Will try it out again tomorrow morning on the water. Keeping my fingers crossed.