I'm building a 1981 115 johnson...how do you check main bearings to make sure they are good besides a visual inspection ?? when the motor was together you could grab the flywheel and push and pull horizontally and hear a very very small clank....
The upper main takes alot of stress and is less lubricated than any part of the motor. The wear occurs on the crank but also inside the assembly. Unfortunately the assembly is not rebuildable and the bearing is mucho $. Well worth replacing if it is suspect. Bearing rollers would have a bluish tint if they had been exposed to extreme heat. Try reinstalling it on the end of the crank once apart and check for movement.
Roller bearings do not (must not) be "tight". They must have a bit of clearance. But they should not have noticeable clunk. Generally, if they are bad, you can tell by looking. They will be blued, pitted, flat spotted, or measurable wear on the crank where they roll. If none of the above, keep on using them.
