Mercury Outboard Cam Bearings

Camshaft bearings support the camshaft in the engine and their low-friction composition allows for its rotation. Cam bearings are positioned along the camshaft inbetween the cams.
Typically, an engine has between 1 and 7 bearings per camshaft, but it depends on your engine type.

It's important that each bearing is installed in its proper position (there is variation in the size of the bearings depending on its intended install position).
If the bearings are placed incorrectly, there can be too much clearance. This allows the camshaft to flex, distorting it. This distortion doesn't allow for proper support or lubrication, leading to wear on your bearings.

Improper install can also result in oil holes being partially or completely covered. This prevents the proper amount of oil from lubricating the camshaft, leading to excessive wear on the bearing. Ensure that the bearings are properly aligned on install to help prevent this issue.