PISTON RING KIT 0.50 YAMAHA 61N-11605-00

Function and technical context

Piston rings are essential components of the internal combustion system that seal the compression chamber during engine duty cycles. They act as a hermetic barrier between the piston and the cylinder walls, preventing leaks of compressed gases into the crankcase and preventing lubrication oil from rising into the combustion chamber. This +0.50 mm oversize kit is installed when the cylinder has been ground to recover its geometry after accumulated wear. Poor ring sealing causes significant loss of compression, bluish smoke in the exhaust, excessive oil consumption and drastic reduction in engine power.

When to replace this part?

Symptoms of advanced wear include measurable compression loss, visible smoke emissions during acceleration, increased oil consumption between service changes, and difficulty starting cold. Although there is no fixed time interval, ring wear is inevitable with hours of operation, especially in marine engines that alternate variable load regimes. Preventive replacement during a cylinder overhaul avoids unforeseen breakdowns in navigation and the need for much more expensive complete engine repairs in port or shipyard.

Equivalent manufacturer part numbers