PISTON YAMAHA 69M-E1631-01-96 PAF2.6-04020001

Function and technical context

The piston is the fundamental component of the internal combustion system, responsible for transforming the thermal energy generated by the explosion of the air-fuel mixture into linear mechanical movement. It works within the cylinder chamber, moving between top and bottom dead center to compress the charge during the compression stroke and expand during the power stroke, transmitting force to the crankshaft through the connecting rod. Its tightness is critical to maintain engine compression, prevent combustion gas leaks and guarantee the mechanical efficiency of the propulsion equipment; Any excessive wear, seizure or breakage directly compromises the available power, increases fuel consumption and can facilitate the entry of water into the crankcase in saltwater or freshwater marine applications.

When to replace this part?

Pistons should be inspected when symptoms such as progressive loss of power, abnormal increase in oil consumption, bluish smoke in the exhaust or audible metallic knocking inside the engine are detected. Although there is no fixed replacement time interval, these components require replacement during engine overhauls for advanced cylinder wear, prolonged thermal erosion, or when freshwater corrosion is evident on inland water vessels. Preventively replacing the piston during an engine overhaul avoids costly subsequent repairs and guarantees full recovery of the compression and power of the propulsion system.

Equivalent manufacturer part numbers