Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 135Get this manual
19Use mallet and tap piston pin into piston and push piston pin tool out 21Make su re lockrings are properly seated in pistor grooves
aPiston PinPiston Pin Tool
20l nstall new piston pin lockrings (one each end of piston pin) with Lockring Installation Tool (9193004A 1) as shown
22Before insta ll ing new piston rings, check gap between ring ends by placing each ring in its respective cy linder, then pushing ring about 12" (13mm) into cyli nder using piston to assure proper position 23 Check end gap of each piston ring with feeler gaugeEnd gap must be within .012" to .024" (O .30mm to 0.61mm) If end gap is greater, check other new piston ri ngs in cyli nder bore until rings (with in tolerance) are found If end gap is less than tolerance, and another ring within tolerance cannot be found, it may be necessary to file some material from pi ston ring end (at gap) If it is necessary to file pi ston ring, be sure that all rough edges are removed after filing