This hydraulic steering cylinder for outboard motors from Ultraflex is the front-mounted and balanced model UC128-OBF/3. The cylinder is mounted on the outboard motor's tilt tube and features a curved LA3 connection arm in a standard/starboard configuration.
The balanced design provides the same number of steering wheel turns from side to side. The cylinder volume is 120 cm³, the thrust force is 450 kg, and the stroke length is 185 mm. The connection for hydraulic hoses is 3/8", while the vent connections use DN5 quick-connect couplings. The adjustable and orientable hose connections allow for orientation adjustments during installation.
The cylinder has a total length of 544 mm and a vertical dimension of 76.2 mm. The internal cylinder diameter is 35 mm. The construction includes a heavy-duty stainless steel cylinder rod, high-strength connections and seals, and a high-strength stainless steel ULTRABOLT connecting bolt. The cylinder end caps are replaceable.
Compatible engine models
The UC128-OBF/3 is documented for Mercury and Mariner 75, 90, and 115 Optimax 2-stroke engines from model years 2004-2018, as well as Honda BF115 and BF130 4-stroke engines from model year 1998 onwards. Engine model, model year, tilt tube, and available mounting space must be checked before installation.
For single-engine installations, a minimum free width of 540 mm is required, as well as 152 mm in the specified clearance directions. For dual engines, the corresponding width dimension is 1,110 mm, and the center-to-center distance of the engines must be at least 650 mm. These dimensions are installation and clearance dimensions and not the product dimensions of the cylinder.
The UC128-OBF system can be used in setups with one engine and one cylinder up to 300 hp. System limits depend on the number of engines, direction of rotation, number of cylinders, and the correct choice of pump, hoses, oil, and connecting rod. The cylinder is not recommended for boats with a maximum speed exceeding 48 knots and is not intended for racing.
System components and spare parts
Compatible system components include the UP25, UP28, UP33, and UP39 hydraulic pumps, pre-assembled Kit OB and Kit OB/R5 hose sets, and OL150 hydraulic oil. The specific pump, hose length, and other system configurations must be selected according to the installation.
The current manufacturer number is 43233T. Documented spare parts include 43248G mounting bracket, 39491T through-rod, 41812Z spacer kit, 41810V plastic cap kit, 39979A hardware/connection arm kit, 40822X ULTRABOLT connection kit, 43255D shaft screws, and 43350X end cap/seal kit. The LA3 connection arm has manufacturer number 40073F and item no. 45.282.23. Replacement of hydraulic spare parts should be carried out by a qualified technician.
Always check the engine's model, year, tilt tube, mounting space, and original part number before purchasing.
Key featuresFront-mounted hydraulic steering cylinder for outboard motors
Balanced design with equal steering wheel turns to both sides
Standard/starboard version with curved LA3 connection arm
Cylinder volume: 120 cm³
Thrust force: 450 kg
Stroke length: 185 mm
3/8" adjustable hose connections and DN5 vent couplings
Stainless steel cylinder rod and ULTRABOLT connecting bolt
CE and UKCA marked
