Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 131Get this manual
Powerhead Reassembly 1If removedspread new crankshaft sealing ring just enough to slide over crankshaft journal
3Lu bricate centerm ain cran kshaft ro ller bearings and races with light oil
"'WARNING
Wear safety glasses when Installing sealing ringsSealIng rings are very brittle and could break apart In flying pieces when being spread
4Place centermain crankshaft roller bea rings on upper and lower main bearing journals