Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 487Get this manual
ATTACHMENTSCONTROL LINKAGE
bPosition attaching kit on transom so that transom bracket is centered on the 15 in(38.1 mm) (Figure 1) at height where the center of Ride-Guide yoke is even with, or not more than 12 in(12.7 mm) above top edge of transom(Figure 3)