Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 184Get this manual
Trim "Out" Angle Adjustment AWARNING
Trim limit switch must never be adjusted so that there is less than 12 in(12.7mm) engagement of the swivel bracket in the transom brackets1Trim outboard to fullIN" position, then trim engine out until pump motor stopsOutward trim of engine must stop so that outboard swivel bracket maintains MINIMUM of 12 in(12.7mm) engagement within transom bracket flangesas shown 2Pull on outboard lower unit to take up all slack in hydraulic cylinders while checking trim limit tilt position IMPORTANT: If pistons retract into trim cylinders more than 118 in(3.2mm) while pulling up on outboard lower unit, it will be necessary to bleed air from hydraulic systemRefer to "Filling and Bleeding the Power Trim System