COLLARIN EJE 1-1/8`` (MG)

Function and technical context

The shaft collar is an axial positioning and retention component that works directly on the boat's tail shaft, acting as a mechanical stop that prevents unwanted longitudinal displacement of the drive shaft. Its function within the propulsion system is critical: it ensures that the shaft maintains its correct position with respect to the hull and the sealing assembly, preventing the forces generated by the propeller during propulsion from displacing the shaft into the interior of the hull. A damaged collar or one with excessive play can cause abnormal vibrations in the drive train, premature wear of the stuffing box or shaft seal, and even water entry into the interior of the boat if the sealing system loses its correct seat. This collar, with reference REC9139MG, is manufactured for 1-1/8 inch diameter shafts, a common measurement on mid-high range Mercury Marine outboard engines and propellers.

When to replace this part?

The most common symptoms that indicate that the shaft collar needs replacement are: noticeable axial play when pushing and pulling the shaft by hand, unusual vibration transmitted to the hull when sailing at certain revolutions, or visible friction and wear marks in the contact area of the collar with its seat. It is recommended to visually inspect the collar at each seasonal inspection and, as a general rule, replace it if it presents galvanic corrosion, cracks or loss of fit on the shaft. Replacing this element preventively during annual maintenance is the best guarantee to avoid breakdowns in the shaft line which, if they occur while sailing, involve stranding, towing and repairs at a much higher cost.