Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 484Get this manual
ATTACHMENTSCONTROL LINKAGE
5Inspection and lubrication of steering head assembly (rotary or straight rack) should be performed once each year (by your Authorized Dealer) or whenever steering mount andor steering head are disassembled, or if steering effort has increasedLubricate with 2-4-C wTeflon