Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 127Get this manual
Connecting Rods NOTE: Photos of connecting rods are no 250 275 engine but are for reference only
1Check connecting rods for alignment by placing rods on surface lateIf light can be seen under any portion machined surfaces, if rod has slight wobble on plateor if .002(0.051 mm) feeter gauge can be inserted between any machined surface and surface plate, rod is bent and must be discarded
5Spa lling: Spalling is the loss of bea ring surfaceand it resembles flaking or chippingSpalling will be most evident on the thrust portion of he connecting rod in line with the "Ibeam General bearing surface deterioration could be caused by or accelerated by improper lubrication
2OverheatingOverheating is visibleasa bluish bearing surface color that is caused by inadequate lubrication or excessive RPM 3Rust: Rust formation on bearing su rfaces cause uneven pitting of su rfacers) $pailing