Comet Pump RW 8518 S, 8.7 GPM 1800 PSI, Belt Drive Pump 11.9hp by | Jul 22, 2026Flow: 29.7 L/min – 7.9 GPM. Piston Guides are Heat Treated Stainless Steel. Exclusive No-Oil-Leak System in the crankcase minimising wear of the piston oil seal (Patented). High Quality Tapered Roller Bearings.