A.Y. McDonald 24050J Stainless Steel Pump End Only 5 GPM 0.5 HPA. Y. McDonald offers a full line of four inch submersibles ranging from 1 2 through 5 horsepower, with flow rates ranging from 5 through 25 GPM. The 24000 Series stainless steel submersibles offer peak capacity performance in 5, 7, 10, 15, 20, and 25 GPM models. All J Series Stainless Steel Submersible Pumps are designed to pump within the 5 GPM range. Sizes are available from 1 2 to 1 1 2 HP. All models are standard with 1 1 4" NPT discharge. A. Y.