I know everyone uses Julios kit..... but there still might be some of these kits in service.
A friend of mine runs one and was having issues with the kit when it was hot out he was going to toss it and start over but decided to disassemble and see if he could figure out why it would not pump when the temps got higher.
He found a thermal switch that is designed to shut the Flowjet pump off if it overheats typically when it is run dry.
Good idea for a bilge or fresh water pump on a boat not so good for our application. He has removed it and the pump works great so far if this changes I will update this post. Here is a picture of his heartache..... .