Review on 🔌 Johnson Pump 28572 750 GPH Bilge Pump Replacement Cartridge - Model No. 32702, Black by Charlie Dillon

I needed to replace the cartridge in my Johnson bilge pump. I have had very good luck with these cartridges over the years. They are much easier to replace than the entire bilge pump assembly should you ever fail. The only reason this pump failed was because it was not being used. My shaft is frozen. If you lubricate the shaft with silicone and turn it on every time. and then they last a long time. I looked at Revain and saw that there were two replacement pumps, one for 500gph like my original pump and the other for 750gph. I was wondering how one cartridge can pump 50% more than another cartridge when they are both the same size. Can there be larger magnets or more windings? So I ordered a 500 gph and 750 gph pump cartridge. Out of curiosity, I decided to test two pump cartridges. I put a cork in my boat and filled it with water. Not really full, but enough to cover the pump with a few inches of water. I put a 500 gallon cartridge in the boat per hour and calculated how long it would take to fill a 5 gallon bucket. It should inflate to a head of about two feet. It took a 500 GPH pump 1 minute and 10 seconds to fill a 5 gallon bucket. Not close to the advertised 500 GPH flow rate. Then I set up a 750 gph pump cartridge and calculated how long it would take to fill a five gallon bucket. I kept the boat at the same water level by adding more water while pumping to keep the pressure the same. The 750 GPM pump took 1 minute and 10 seconds to fill a 5 gallon bucket. Thus, both have the same flow rate at a two foot drop. I found it hard to believe that a pump the same size as a 500 GPH pump could pump 50% more water. I was right, it's impossible. When I took the pumps out of the box I felt a slight weight difference so I decided to weigh two pumps, there is a slight difference in the weight of the two pumps, 500 GPH weighs 6.9 ounces, 750 GPH weighs 8 ounces. So the difference between the two pumps is 1.1 ounces. It could be more windings or a heavier magnet, I don't know, but it's not enough to make a difference. I will continue to use the 500 GPH cartridge and am happy with it. I see no reason to spend extra money on a 750gph cartridge when it has the exact same flow rate as a 500gph cartridge. If this helped you, let me know by clicking on the message.