Jabsco - Sealed Macerator Self-Priming Pump - 12V - 18590-2092 Self-Priming Macerator Pump with Run-Dry Protection. Waste Evacuation The Jabsco 18590 series DC macerator pump unit is the ideal solution for emptying marine holding tanks when not in a discharge restricted area. Self priming to 5ft this pump will empty a typical 30 gallon (115 Liter) holding tank in less than 3 minutes. Duty cycle of the pump is 15 minutes continuous which means a 180 gallon (680 liter) can be emptied in a single o