HP Injector is a precise synthetic formulation that exceeds the lubrication demands of modern two cycle motors. Today’s twocycle outboard motors operate at higher temperatures and at leaner oil and fuel ratios than older motors. This difficult operating environment requires proper lubrication technology to keep motors running long and strong. HP Injector is a premium lubricant engineered with AMSOIL synthetic base oils and MAXDOSE advanced additives. It contains up to 30 percent more additives than other TC-W3 two-cycle oils for “super clean” operation. And because AMSOIL synthetic oils are more durable, they are perfect for lean mixture operations. In addition, this AMSOIL exclusive product produces low smoke and odor and has low aquatic toxicity properties, making it ideal for boats.
HP Injector improves engine life. It prevents deposits that cause ring sticking and ring jacking (carbon build-up behind the ring, forcing it outward), a phenomenon that occurs in modern DFI outboard motors. HP Injector prevents wear. It has excellent lubricity properties and provides a good lubricating oil film, protecting pistons and bearings. HP Injector prevents rust, an important feature where motors are subjected to water. HP Injector provides superior performance in direct fuel injected (DFI), electronic fuel injected (EFI) and carbureted outboard motors, as well as other recreational equipment.
Quick Facts
• Superior performance in DFI outboard motors
• Prevents piston and combustion chamber deposits
• Prevents “ring jacking” common to DFI outboards
• Low smoke, low odor product
• Contains up to 30 percent more additives for “super clean” operation
• Prevents wear for long engine life
• Prevents rust
• Multi-functional and recommended for use in many two-cycle motors
• Low aquatic toxicity
• Recommended for use as injection oil or at a 50:1 pre-mix
Typical Technical Properties
HP Injector Synthetic 2-Cycle Oil (HPI)
Kinematic Viscosity @ 100°C, cSt (ASTM D-445)...............................................................................7.7
Kinematic Viscosity @ 40°C, cSt (ASTM D-445)...............................................................................38.7
Viscosity Index (ASTM D-2270)........................................................................................................173
Pour Point, °C (°F) (ASTM D-97)..............................................................................................-46 (-51)
Flash Point, °C (°F) (ASTM D-92).............................................................................................86 (187)
Fire Point, °C (°F) (ASTM D-92)................................................................................................86 (187)
Applications
HP Injector is recommended for use in all two-cycle outboard motors including, but not limited to, Mercury® EFI & Optimax®, Johnson® and Evinrude® FICHT® and E-TEC™, Yamaha® HPDI, Nissan® and Tohatsu® TLDI®, Suzuki®, Mariner® and Force®. Also recommended for use in all two-cycle personal watercraft and jet boats, as well as snowmobiles, motorcycles and ATVs.
Use as injection oil or as 50:1 pre-mix (2.6 oz. per U.S. gallon of gas) where NMMA TC-W3 or API TC oils are specified. Compatible with mineral and synthetic TC-W3 type two-cycle oils, however, mixing two-cycle oils should be minimized.
Amsoil Sybthetic 2-Cycle Oil Recommendations

Equipment manufacturers and motor builders have redesigned two-cycle motors to reduce emissions and increase fuel economy. These changes have increased operating temperatures, reduced oil consumption and incorporated direct fuel injection and exhaust power valves. AMSOIL 2-Cycle Oils are designed to maximize performance in all types of engine designs and are optimized for select applications.
Even though AMSOIL 2-Cycle Oils have been optimized for specific applications, they are multi functional and recommended for use in many areas. The chart rates each oil’s performance abilities per application as follows:
Excellent: The primary recommendation for the oil. The oil is specifically designed for the operating conditions of the motors in these markets. There is only one “Excellent” recommendation per category.
Very Good: A main recommendation for the oil. Identifies an oil that is very good for the operating conditions of these motors.
Good: A secondary recommendation for an oil. The oil was not specifically designed for these applications. However, the chemistry in the oil is suited to the operating conditions of these motors.
Not Recommended: Identifies applications where the product was not intended for use.
Racing:
(1) Not recommended for long-term use in outboard motors as a TC-W3 type oil, although excellent as a race oil for short term use where motors are periodically inspected.
(2) Excellent for racing or modified motors. Very good for recreational use.
*Recommended for all direct fuel injected (DFI), electronic fuel injected (EFI) and carbureted motors. Outboard motors include Mercury® Optimax,® Johnson® & Evinrude® FICHT® & E-TEC,™ Yamaha® HPDI, Nissan® & Tohatsu® TLDI.®