Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 459Get this manual
ATTACHMENTSCONTROL LINKAGE
STEERING LINK ROD INSTALLATION
IMPORTANT: The steering link rod that connects the steering cable to the engine must be fastened using special washer head bolt ("a"Part Number 10-14000) and self locking nuts ("b""c"Part Number 11-34863)These locknuts must never be replaced with common nuts (non locking) as they will work loose and vibrate off freeing the link rod to disengage
WARNING
Disengagement of steering link rod can result in the boat taking full, sudden, sharp turnThis potentially violent action can cause occupants to be thrown overboard exposing them to serious injury or death1Assemble steering link rod to steering cable with two flat washers (d) and nylon insert locknut ("b"Part Number 11-34863)Tighten locknut (b) until it seats, then back nut off 14 turn2Production OutboardsAssemble steering link rod to engine with special washer head bolt ("a"Part Number 10-14000) and nylon insert locknut ("c"Part Number 11-34863)First torque bolt (a) to 20 lbft(27 Nm), then torque locknut (c) to 20 lbft(27 Nm)High Performance OutboardsAn access hole is provided through the bottom cowl to ease installation of the link rod connecting boltRemove the BACK plug for installation and reinstall after installation