UC128-OBF Front Mount Cylinder
The UC128-OBF is a balanced front mount cylinder designed for outboard engines, offering a smooth and responsive steering experience. It features a heavy-duty stainless steel cylinder rod, seals, and link assemblies, ensuring durability and reliability.
Key Features
- Balanced design with equal lock-to-lock wheel turns from port to starboard.
- Adjustable boss style fittings for easy installation.
- High resistance stainless steel connection bolt (ULTRABOLT).
- Replaceable cylinder end caps.
- Simple to install and compatible with most 2 and 4-stroke outboard engines.
- Recommended for use with UP25, UP28, UP33, and UP39 series helms and preassembled hoses (Kit OB and Kit OB/R5).
Applications
The UC128-OBF front mount cylinder is suitable for a wide range of outboard engines. For twin engine applications, specific starboard (UC128-OBF) and port (UC128P-OBF) cylinders are required, along with appropriate tie bars.
Important Note: This cylinder is not recommended for installations where boat speed exceeds 55 mph (48 knots) or 65 mph (56 knots) for dual engine, dual cylinder, and counter-rotating engine applications. It is not intended for racing applications.
Specifications
| Model | Part No. | Description | Volume | Output Force | Internal Diameter | Stroke | Fittings for high pressure flex hose | Bleed Fittings |
|---|---|---|---|---|---|---|---|---|
| UC128-OBF/1 | 43231N | Front mount cylinder, starboard version | 120 cc (7.3 cu.in.) | 450 kg (992 lbs) | 35 mm (1.37") | 185 mm (7.28") | 3/8" | DN5 quick connect |
| UC128-OBF/2 | 43232R | Front mount cylinder, starboard version | ||||||
| UC128-OBF/3 | 43233T | Front mount cylinder, starboard version | ||||||
| UC128P-OBF/1 | 43234V | Front mount cylinder, port version | ||||||
| UC128P-OBF/2 | 43235X | Front mount cylinder, port version |
Splashwell Dimension Requirements
For twin engine applications, the minimum engine center distance is 650 mm (26").
| Dimension | Engine No. 1 | Engine No. 2 |
|---|---|---|
| A | 540 mm (21.25") | 1110 mm (43.70") |
| B | 152 mm (5.98") | 152 mm (5.98") |
| C | 152 mm (5.98") | 152 mm (5.98") |
UC128-OBF Link Arms
Link arm kits are available for adapting the UC128-OBF cylinder to existing outboard engines. These kits are recommended for initial installation only and not as a retrofit. Installation should be performed by qualified technicians.
"STARBOARD" Link Arms
- LA1 (Part No. 40045A) for UC128-OBF/1
- LA2 (Part No. 40046C) for UC128-OBF/2
- LA3 (Part No. 40073F) for UC128-OBF/3
"PORT" Link Arms
- LA1P (Part No. 40104P) for UC128P-OBF/1
- LA2P (Part No. 40105S) for UC128P-OBF/2
UC128-OBF Cylinder Applications by Engine Manufacturer
The following table lists compatible engine models, years, and the corresponding cylinder part numbers:
| ENGINE | MODEL | YEAR | CYLINDER | P. NO. |
|---|---|---|---|---|
| Mercury® | 115-125-150 EFI 2S | 1990-2007 | UC128-OBF/1 | 43231N |
| 225-250 EFI 2S | 2000-2007 | UC128-OBF/1 | 43231N | |
| 75-90-115 OPTIMAX | 2004-2018 | UC128-OBF/3 | 43233T | |
| 135-150-175 OPTIMAX | 1999-2018 | UC128-OBF/1 | 43231N | |
| 200-225-250 OPTIMAX | 1999-2018 | UC128-OBF/1 | 43231N | |
| RACING 300 OPTIMAX | 1999-2011 | UC128-OBF/1 | 43231N | |
| Mariner® 100-115 EFI 4S | 2007-to date | UC128-OBF/1 | 43231N | |
| 250 SALTWATER EFI 4S | 2007-2011 | UC128-OBF/1 | 43231N | |
| 135-150-175-200 VERADO L4 | 2004-2012 | UC128-OBF/1 | 43231N | |
| FOURSTROKE / PRO XS 175-200 V6 | 2018-to date | UC128-OBF/1 | 43231N | |
| FOURSTROKE / PRO XS 225-300 V8 | 2018-to date | UC128-OBF/1 | 43231N | |
| Evinrude® | E75-E90 2S | 2004-to date | UC128-OBF/2 | 43232R |
| E115-E130-E135 2S V4 | 1995-2020 | UC128-OBF/2 | 43232R | |
| E150-E175-E200-E225-E250-E300 2S V6 | 1995-2020 | UC128-OBF/2 | 43232R | |
| 115C-130B 2S | 1990-2008 | UC128-OBF/2 | 43232R | |
| 75C-90 2S | 1998-2008 | UC128-OBF/2 | 43232R | |
| F70 4S | 2010-to date | UC128P-OBF/1 | 43234V | |
| 150F-200F-250G 2S | 1990-2008 | UC128-OBF/2 | 43232R | |
| 150 HPDI VMAX 2S | 1996-2007 | UC128-OBF/2 | 43232R | |
| Yamaha® | 175-200-225-250-300 HPDI VMAX 2S | 2000-2008 | UC128-OBF/2 | 43232R |
| F115-F150 EFI 4S | 2000-2008 | UC128-OBF/2 | 43232R | |
| F200-F225-F250 4S | 1999-2007 | UC128-OBF/2 | 43232R | |
| F115-F130-F150D-F150F-F175A-F200F-F200G L4 | 2002-to date | UC128-OBF/1 | 43231N | |
| F200-F225-F250-F300 V6 4S | 2004-to date | UC128-OBF/2 | 43232R | |
| Honda® | BF75-BF90 4S | 1995-to date | UC128-OBF/1 | 43231N |
| BF115-BF130 4S | 1998-to date | UC128-OBF/3 | 43233T | |
| BF135-BF150 4S | 2005-to date | UC128-OBF/1 | 43231N | |
| BF150 V-TEC 4S | 2008-to date | UC128-OBF/1 | 43231N | |
| BF175-BF200-BF225-BF250 4S | 2001-to date | UC128-OBF/1 | 43231N | |
| Suzuki® | DF70-80-90 4S | 1998-to date | UC128-OBF/2 | 43232R |
| DF100-115-140 4S | 2008-to date | UC128-OBF/1 | 43231N | |
| DF150-175-DF200 L4 4S | 2006-to date | UC128-OBF/1 | 43231N | |
| DF200-DF225-DF250-DF300-V6 4S | 2004-to date | UC128-OBF/2 | 43232R | |
| Tohatsu® | 115-120-140 2S | 2004-to date | UC128-OBF/2 | 43232R |
| 70-90-115 TLDI 4S | 2004-to date | UC128-OBF/1 | 43231N | |
| MFS 50-60-75-90-100-115 4S | 2018-to date | UC128-OBF/1 | 43231N | |
| BFT 115-150-200-225-250 4S | 2014-to date | UC128-OBF/1 | 43231N | |
| BFT60-75-80-90-100 4S | 2015-to date | UC128-OBF/1 | 43231N | |
| Selva® | 80 PORTOFINO/TIGERSHARK 2S | 1995-2008 | UC128-OBF/1 | 43231N |
| 150 WHITE SHARK 2S | 2001-2007 | UC128-OBF/2 | 43232R | |
| 100EFI MARLIN-115 EFI NARWHAL | 2000-to date | UC128-OBF/2 | 43232R | |
| 225 BEAKED WHALE 4S | 2019-to date | UC128-OBF/2 | 43232R | |
| 100-150EFI KILLER WHALE 4S- 200 SEI WHALE 4S | 2000-to date | UC128-OBF/1 | 43231N | |
| Johnson® | BJ90-115-140 4S | 2001-2007 | UC128-OBF/1 | 43231N |
| J90-115 V4 2S | 1995-2007 | UC128-OBF/2 | 43232R | |
| J150-175 V6 2S | 1995-2007 | UC128-OBF/2 | 43232R | |
| J200-225 V6 4S | 2004-2007 | UC128-OBF/2 | 43232R | |
| OXE® | 125-150-175-200HP DIESEL 300HP DIESEL | 2018-to date 2020-to date | UC128-OBF/1 UC128-OBF/1 | 43231N 43231N |
| COX® | 300HP | 2020-to date | UC128-OBF/2 | 43232R |
| Neander Shark® | DTORQUE 111 | 2018-to date | UC128-OBF/1 | 43231N |
| Parsun® | F300 | 2023-to date | UC128-OBF/2 | 43232R |
Note: For higher horsepower applications, a high-performance SilverSteer™ cylinder is recommended. Suzuki engines manufactured between 1998 and 2008 may require the optional KIT SU 41954W.
Warning: These recommendations are for general reference. Final selection should be made with the assistance of a qualified installation technician. For further information, please contact Technical Service.
Order Guide
The following table outlines the components and quantities required for different engine configurations:
Single engine, Single cylinder
| SYSTEM | APPLICATION | WHEEL TURNS | COMPONENTS | MODEL | Q.TY |
|---|---|---|---|---|---|
| Single engine | Up to 300 hp max | 4.8 (UP25) | Cylinder Helm pump Hose Kit Oil Steering wheel | UC128-OBF UP25 or UP28 KIT OB OL 150 (Wheel selection) | 1 1 1 2 1 |
| 4.3 (UP28) | |||||
| For a second station add: 1 UP25 or UP28 helm pump, 1 KIT OB-2S fitting kit, 1 KIT OB, 1 OL 150, 1 steering wheel | |||||
Dual engine, Single cylinder
| SYSTEM | APPLICATION | WHEEL TURNS | COMPONENTS | MODEL | Q.TY |
|---|---|---|---|---|---|
| Dual engine | Up to 300 hp max (non-counter rotating engine) | 4.8 (UP25) | Cylinder Helm pump Hose Kit Oil Steering wheel | UC128-OBF UP25 or UP28 KIT OB OL 150 (Wheel selection) | 1 1 1 2 1 |
| Up to 500 hp max (counter rotating engine) | 4.3 (UP28) | Tie bar | A96 | 1 | |
| For a second station add: 1 UP25 or UP28 helm pump, 1 KIT OB-2S fitting kit, 1 KIT OB, 1 OL 150, 1 steering wheel | |||||
Dual engine, Dual cylinder
| SYSTEM | APPLICATION | WHEEL TURNS | COMPONENTS | MODEL | Q.TY |
|---|---|---|---|---|---|
| Dual engine | Up to 500 hp max (non-counter rotating engines) | 6.1 (UP39) | Cylinder Cylinder Port Helm pump Hose Kit Oil Tie bar Steering wheel Connection Kit | UC128-OBF UC128P-OBF UP39 or UP45 KIT OB OL 150 A95 (Wheel selection) KIT OB-2C | 1 1 1 1 3 1 1 1 |
| Up to 600 hp max (counter rotating engines) | 5.3 (UP45) | ||||
| For a second station add: 1 UP39 or UP45 helm pump, 1 KIT OB-2S fitting kit, 1 KIT OB, 2 T fittings 39502 V, 1 OL 150, 1 steering wheel | |||||
Warning: The UC128-OBF front mount cylinder is not recommended for use in installations where the boat speed exceeds 55 mph (48 knots) or 65 mph (56 knots) in dual engine, dual cylinder and counter rotating engines application. Not intended for use in racing applications.
Dual engine dual cylinder application diagram
Diagram showing dual engine dual cylinder application.
Notes:
- For triple outboard engine, dual cylinder applications, please refer to the tie-bar section.
- For any further and detailed information, please contact our Technical Service.
- For high performance applications, SilverSteer™ systems are recommended.
