Yamaha outboard motors utilize a hydraulic tilt and trim system to raise and lower the outboard engine. This allows boaters to easily adjust the trim angle of the engine for optimal performance and efficiency.
The hydraulic fluid used in the tilt and trim system is a specialized type, made specifically by Yamaha. However, finding the OEM fluid can be difficult and expensive. Fortunately, there are several viable substitutes available.
With some key considerations, boaters can safely use alternative fluids in their Yamaha tilt and trim systems.
Recommended Yamaha Tilt Trim Fluid Alternatives
Here are some excellent fluids that can be safely substituted in place of Yamaha hydraulic tilt and trim fluid:
- Amsoil Low Viscosity ATHM
- Echo Power Blend Trimmer & Edger Oil
- Lucas Oil Products Hydraulic Oil Protectant
- Maxima Hydraulic Oil
- SeaStar Tilt and Trim Fluid
- Shell Tellus S2 VX 32
- Valvoline Premium hydraulic oil
- Castrol Hyspin AWS 32
- Rotella Hydraulic Oil ISO 32
- Mobil DTE 24 Hydraulic Oil
Let’s talk about them in detail a little bit!
Amsoil Low Viscosity ATHM
Amsoil Low Viscosity ATHM is engineered specifically for marine tilt and trim systems. It has optimized anti-wear additives and rust inhibitors. The viscosity is a perfect match for Yamaha systems at ISO 32.
Made from premium base oils and meets industry specifications. Excellent value for a full synthetic fluid.
Echo Power Blend Trimmer & Edger Oil
This oil is designed for 2-stroke outdoor power equipment, but has the ideal properties for Yamaha tilt and trim as well.
It has anti-wear protection and stabilizing agents. The viscosity falls within specifications at ISO VG 34.
No detergent additives to leave deposits. Provides excellent lubrication.
Lucas Oil Products Hydraulic Oil Protectant
Formulated for high pressure hydraulic systems with premium base oils and zinc anti-wear additives. It has excellent oxidation resistance and thermal stability. Contains no detergents.
Viscosity rating is ISO VG 32, making it an ideal Yamaha system substitute. Protects against wear and corrosion.
Maxima Hydraulic Oil
Maxima Hydraulic Oil is used by many ATV and motorcycle racers in their clutch and brake systems. It has shear stability, anti-wear protection and maintains a consistent viscosity.
The ISO rating is 32, matching the OEM spec. Contains no detergents which helps maintain the cleanliness of the system.
SeaStar Tilt and Trim Fluid
SeaStar makes this fluid specially for marine tilt/trim systems. It is fully synthetic ISO 32 with anti-corrosion and anti-wear properties. Compatible with nitrile rubber seals.
Provides optimal lubrication and has UV inhibitors which help resist fluid breakdown.Marketed under the Sierra brand name as well.
Shell Tellus S2 VX 32
A premium hydraulic fluid made by Shell.
The viscosity grade is ISO VG 32. Contains zinc-based anti-wear additives and oxidation inhibitors.
Has excellent demulsibility and water separation traits which help resist fluid contamination. An ideal choice for Yamaha tilt and trim systems.
Out of all of these good options, the Amsoil Low Viscosity ATHM is likely the best direct substitute for genuine Yamaha fluid.
Made specifically for marine applications and contains premium zinc anti-wear compounds.
Valvoline Premium hydraulic oil
- ISO grade 32 viscosity
- Contains anti-wear and anti-corrosion additives
- Formulated for high pressure systems
- Protects against rust and oxidation
- No detergents which helps keep systems clean
Castrol Hyspin AWS 32
- Anti-wear hydraulic oil rated at ISO VG 32
- Excellent water separation and demulsibility
- High shear stability and low foaming
- Protects against corrosion and oxidation
- Contains zinc-based additives for wear protection
Rotella Hydraulic Oil ISO 32
- Made by Shell Rotella heavy duty engine oil brand
- ISO 32 viscosity grade matches Yamaha spec
- Thermally stable and high viscosity index
- Contains anti-oxidant, anti-rust, anti-foam agents
- Protects against wear with zinc-based additives
Mobil DTE 24 Hydraulic Oil
- ISO grade 32 with high viscosity index
- Excellent thermal and oxidation stability
- Contains demulsifier additives for water separation
- Formulated for vane and piston pumps
- Anti-wear protection for high pressure systems
Overview of Yamaha Tilt and Trim Systems
Yamaha outboards have used hydraulic tilt and trim systems since the 1980s. The system consists of an electric pump mounted on the engine, connected to a hydraulic cylinder.
When activated, the pump forces hydraulic fluid into the cylinder, extending the piston and tilting the engine up or down. Trim tabs on the lower unit then hold the desired trim angle.
The hydraulic fluid serves several key functions:
- Transmits power from the pump to the tilt cylinder
- Lubricates the internal components
- Protects metal surfaces from corrosion
- Removes heat from the system
Yamaha recommends using their own brand of hydraulic fluid for optimal performance and longevity.
However, the OEM fluid can be difficult to find and expensive, retailing over $20 per quart.
The good news is Yamaha systems can safely utilize other hydraulic fluids not specifically made by Yamaha.
Also Read: Alternatives To Penta Power Steering Fluid.
Important Considerations for Alternative Fluids
While other hydraulic fluids can work in Yamaha systems, there are some important factors to consider:
- Viscosity – The fluid needs to be within the proper viscosity range to flow through the system and provide sufficient lubrication. Yamaha’s fluid is approximately ISO VG 32.
- Detergent additives – Many hydraulic fluids contain detergent additives which can leave deposits inside the tilt/trim components over time. Non-detergent fluids are preferable.
- Anti-wear properties – The fluid must be able to withstand high pressures and provide adequate wear protection. Zinc anti-wear additives are ideal.
- Anti-corrosion properties – Hydraulic fluid also provides corrosion resistance for internal metal components. Using a fluid with anti-corrosive additives is recommended.
- Seal compatibility – Some fluids may cause seals and O-rings to swell, whereas others could shrink them and cause leaks. Using a compatible formula is key.
By using a hydraulic fluid that meets these requirements, Yamaha boat owners can avoid problems and maintain proper functionality.
Mixing Different Brands of Hydraulic Fluid
A common question boat owners have is whether or not different types or brands of fluid can be mixed together in the tilt and trim system.
The short answer is yes, different hydraulic fluids are generally compatible and miscible with each other. However, there are some cautions:
- Mixing may dilute the performance additives present in one brand. It’s best to completely flush the system when switching fluid types rather than just adding new fluid if possible.
- Blending two fluids of different viscosities will result in a viscosity between the two. This could push the viscosity out of the optimal range for the Yamaha system.
- Mixing lubricants from vastly different chemical families (like high water-content fluids with anhydrous types) can result in contamination issues and may cause abrupt viscosity shifts.
Overall, it’s advisable to stick with one fluid brand rather than continually adding different types unless performing periodic complete fluid changes. Mixing similar formulas from major hydraulic oil brands (like Shell, Chevron, etc) is low risk. But mixing vastly different chemical technologies should be avoided for best performance.
Flushing the System When Changing Hydraulic Fluid Brands
To fully remove old fluid and debris when switching between fluid types, Yamaha boat owners should perform a complete flush procedure:
- Disconnect the hoses from the tilt/trim pump and route them into a drain pan.
- Actuate the pump up and down several times to expel all old fluid from the hoses and cylinder.
- Refill the reservoir with the new hydraulic fluid. Operate the pump again until the new fluid exits the hoses.
- Reconnect the hoses being careful not to introduce any contaminants into the system.
- Top off the reservoir and bleed any remaining air per Yamaha’s bleed procedure.
- Verify proper fluid levels in the reservoir after completing the process.
This flush helps purge all prior fluid remnants and any potential contaminants from the system. It allows the fresh fluid to fully circulate and lubricate components without mixing with old fluid. Periodic complete flushing is recommended for maximum performance and longevity.
Symptoms of Using the Wrong Hydraulic Fluid
While the recommended substitutes should perform reliably, using the incorrect type of fluid by accident could result in some issues:
- Poor trim response and slower actuation speed could indicate excessively thick fluid starving the pump.
- Leaks around o-rings and seals may be caused by fluid incompatibility shrinking/swelling the elastomers.
- Noisy pump operation can signal a loss of lubrication and increased internal wear.
- Difficulty bleeding air from the system could indicate fluid has lost its natural demulsibility properties which allow air bubbles to separate.
- Corroded parts inside the pump housing or cylinder barrel may be caused by fluid without proper rust inhibitors.
- Overheating pump and hot trim cylinder may indicate fluid has poor thermal conductivity.
If any of these problems arise after changing tilt/trim fluid brands, flush the system to troubleshoot the cause before severe damage occurs internally.
Also Read: Alternativs To Power-Pole Fluid.
Frequently Asked Questions (FAQ)
The top recommended substitutes are Amsoil Low Viscosity ATHM, Echo Power Blend oil, Lucas Hydraulic Oil Protectant, Maxima Hydraulic Oil, SeaStar Tilt and Trim Fluid, or Shell Tellus S2 VX fluid. All are ISO VG 32 hydraulic oils with anti-wear additives compatible for Yamaha systems.
Look for an ISO 32 grade hydraulic fluid with high zinc content, rust prevention, and no detergent additives. Good examples are Amsoil ATHM, Lucas Marine Oil, Shell Tellus S2 VX, or SeaStar T&T fluid. Always confirm fluid compatibility before using in Yamaha systems.
Yes, standard hydraulic fluids can be suitable substitutes as long as they meet the viscosity, lubrication, and additive requirements. General purpose hydraulic oils may work but a dedicated marine tilt/trim fluid is best. Completely flush old fluid when switching brands.
Power steering fluid is not directly interchangeable with Yamaha tilt/trim fluid. While some formulas may have the correct viscosity, they often contain detergents which can leave deposits. Use a high quality marine hydraulic fluid instead for best performance.
While genuine Yamaha hydraulic fluid provides optimal results, finding alternatives saves money and ensures boaters can keep their tilting systems running smoothly. There are several high quality fluids that meet all the requirements – good lubrication, correct viscosity, anti-wear protection and demulsibility.
Brands like Amsoil, Lucas and SeaStar offer direct tilt/trim fluid replacements for Yamaha systems. Follow the recommendations here and your boat will benefit from smooth, reliable trimming capability all season long.