COLLAR PLANO 25mm. (AL)

Function and technical context

The 25 mm flat aluminum collar is an axial fastening and positioning element that works on the transmission assembly or propulsion shaft of outboard and stationary marine engines. Its main function is to limit the longitudinal displacement of rotating components - such as shafts, gears or pulleys - keeping them in the correct working position within the power train. As it is a piece made of aluminum, it offers an excellent relationship between lightness and resistance to corrosion in saline marine or freshwater environments. If this collar wears, cracks or loses its seat, the component it retains can move axially, generating clearances, vibrations, mechanical noise and, in severe cases, failure of the transmission assembly or breakdown of the adjacent sealing seal.

When to replace this part?

The most common symptoms of a damaged flat collar are unusual vibrations in the drive shaft, metallic knocking noise at certain revolutions, and noticeable axial play when manually moving the shaft with the engine stopped. It is recommended to visually inspect this component during each seasonal maintenance, checking that it does not present deformations, severe corrosion or cracks on its perimeter. Replacing it preventively during scheduled maintenance avoids more costly breakdowns in navigation, especially in areas where technical assistance is difficult.