Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 242Get this manual
7Uneven Wear: Uneven wear could be caused by bent connecting rod cClean PISTON PIN END of connecting rod, using same method as in Step "b", preceding, but using 320 grit carborundum cloth instead of crocus clothdThoroughly wash connecting rods to remove abrasive gritRecheck bearing surfaces of connecting rodsReplace any connecting rod(s) that cannot be properly "cleaned up Lubricate bearing surfaces of connecting rods (which will be re-used) with light oil to prevent rust
51853Uneven Wear Between Arrows
Thermostats
1Inspect thermostat covers and cylinder head covers (thermostat opening) for cracks and corrosion damage that could cause leakageReplace parts as necessary2Remove and thermostatdiscard gasket from each