Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 191Get this manual
Propeller Shaft INSPECTION 1Clean propeller shaft assembly with sotvent and dry with compressed air
6Inspec sliding lutchCheck reverse gear and forward gear clutch "jaws"Rounded "jaws" ind icate one or more of the followingaImproper shift cable adjustmentbImproper shift habits of operator(s) (shift from neutral to reverse gear too slowly)cEngine idle speed too high (while shifting)
2Inspect bearing carrieroit seal surfaces for groovesRun fingernail across seal surface to check for grooveReplace shaft jf groove is found3Visually check bearing surfaces of propeller shaft for pittinggrooves, scoring, uneven wear or discoloration (bluish color) from overheatingReplace shaft and corresponding needle bearing if any of the above conditions are found (Bearing carrier needle bearing contacts propeller shaft just in front of oil seal surfaceForward gear bearing contacts propeller shaft in front of sliding cl utch splines 4Inspect propeller shaft splines for wear andor corrosion damage5Check propeller shaft for straightnessUse either method, followingBalance Wheels Place propeller shaft on balance wheelsRotate propeller shaft and observe propeller end of shaft for "wobble"Replace shaft if any "wobble" is observed