Shop by Brand Yamaha OutboardPiston/Piston Kit ; Piston Pin ; Piston Ring Back Piston Ring 66T-11604-00 0.25 Viewer:793 OEM No. : 66T-11604-00-0.25 For YAMAHA Outboard 40 HP You May Also Be Interested In Piston Ring 6J8-11601-21-00 0.50 Piston Kit 688-11636-03 0.50 Gasket, Exhaust Tube 14212-96310-000 Crank 6F5-11412-11