Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 94Get this manual
7Reinstall attenuator cover with locknuts and flat washers as shownTighten locknuts to 60 lbin(6.8 Nm) aAir Ball CoverFuel Connector
aAttenlualor Cover
bLocknu ts
Synchronizing Carburetors