Two-Cycle Oil

Two-Cycle Oil

Two-cycle engines remain the workhorses in recreational equipment, including outboard motors, motorcycles, snowmobiles and personal watercraft, as well as in lawn and garden applications like lawn mowers and weed eaters. Design changes over recent years have included direct fuel injection engines, in which fuel is injected directly into the combustion chamber, and exhaust power valves, which improve combustion efficiency at varying RPM. These design changes have allowed two-cycle engine manufacturers to effectively reduce emissions, improve fuel efficiency and decrease oil consumption. Today's two-cycle motors of all types require specialized oil technology to deliver maximum engine protection, dependable operation and long service life.

As the leader in two-cycle oil technology, Amsoil has performed extensive research in developing a new line of revolutionary, specialized oils called the "Fabulous Four." Amsoil Interceptor Synthetic 2-Cycle Oil (AIT) was the first new oil to be introduced. It is primarily recommended as an injector oil or at a 50:1 mix ratio in carbureted, electronic fuel injected (EFI) and direct fuel injected (DFI) snowmobiles, personal watercraft, motorcycles and ATV's. Formulated with wax-free premium quality synthetic esters and a specialized additive package, Interceptor is designed to address the exhaust valve sticking problems associated with certain snowmobile models.

HP Injector
High-Performance Interceptor
Dominator Racing Oil
HP Injector (HPI)
(Injection or 50:1 Pre-Mix)
Saber Professional 100:1
Outboard* Excellent Not Recommended Racing (1) Not Recommended
Snowmobile* Motorcycle*
& ATV*
Very Good Excellent Racing (2) Very Good (Pre-Mix Only)
Personal Watercraft*
& Jet Boat*
Very Good Excellent Racing (2) Very Good (Pre-Mix Only)
Chain Saw, Chop Saw,
& Pump
Not Recommended Good Very Good Excellent
Weed Eater, Blower & Lawn Mower Not Recommended Good Very Good Excellent
Moped, Scooter & Go-Cart Not Recommended Good Very Good Excellent


Interceptor Amsoil Interceptor Synthetic 2-Cycle Oil is formulated with a proprietary blend of the finest synthetic base oils and additives available today. This unique Amsoil chemistry represents a breakthrough development in the field of two-cycle engine lubrication.

The backbone of Amsoil Interceptor 2-Cycle Oil is a specially developed molecularly saturated synthetic base oil. This, combined with a "double treat" additive package, ensures exceptional lubricity, cleanliness and optimum clean-burning characteristics. Extensive research and testing, including a full snowmobiling season in severe Rocky Mountain applications, has proven that wear on cylinders, pistons and bearings is dramatically reduced. And with up to 30 percent more detergency and dispersancy than typical two-cycle oils, Amsoil Interceptor virtually eliminates damaging deposits on piston skirts, ring grooves and exhaust power valves.


Amsoil Interceptor Synthetic 2-Cycle Oil is recommended as an injector oil or at a 50:1 mix ratio in carbureted, electronic fuel Injected (EFI) and direct fuel injected (DFI) snowmobiles, personal watercraft, motorcycles, ATVs and jet boats, including, but not limited to, those manufactured by Bombardier®, Yamaha®, Arctic Cat®, Polaris®, Kawasaki®, Suzuki® and Honda®.

It is recommended wherever API TC and JASO FC two-cycle oils are specified. Interceptor is compatible with and recommended as a replacement for all mineral and synthetic manufacturer branded two-cycle oils. For top performance, mixing is not recommended.

400,000 miles of severe snowmobile field testing with no deposit buildup, power valve sticking, ring sticking, or engine failures. Subjected to adverse field testing conditions in the Rocky Mountains, including long trail rides, high RPM powder riding and steep hill climbs, Amsoil Interceptor demonstrated superior wear protection and outstanding deposit control.

Arctic Cat 600 Power Valves

No carbon deposits are detectable in the functioning region of the exhaust power valves, resulting in "no stick" performance, continuous valve operation and reduced maintenance.

Arctic Cat 600 PistonsArctic Cat Heads

Pistons show no scoring, little or no wear and no heavy deposits, and wrist pins show no discoloration from heat. In fact, the original machine markings on the pistons are still visible.

Saber Synthetic 100:1 Pre-Mix 2-Cycle Oils

AMSOIL Saber Outboard 2-Cycle Oil AMSOIL Saber Professional 2-Cycle Oil Asmoil Saber Professional (ATP) and Outboard (ATO) Synthetic 100:1 Pre-Mix 2-Cycle Oils are formulated with exclusive AMSOIL synthetic base oils and premium additives. Designed for lean mix ratios in two-cycle motors, Saber 2-Cycle Oils have excellent lubricity and cleanliness properties, controlling friction and preventing wear, plug fouling, ring sticking and exhaust port blocking. Amsoil Synthetic 100:1 2-Cycle Oils have been protecting and providing improved performance in two-cycle motors since 1973.

Saber Professional

Saber Professional (ATP) is specifically designed for small engines including, but not limited to, chain saws, lawn equipment, blowers, chop saws, pumps, scooters and go-carts. It is also very good for use in motorcycles, snowmobiles, ATVs, jet boats and personal watercraft. Saber Professional is formulated with high temperature detergent additives that prevent hard carbon deposits from forming in these hot operating motors. Saber Professional is “smokeless” and delivers as much as 30 percent fewer emissions at 100:1 mix ratios than oils mixed at 50:1. Equipment operators subjected to smoke and fumes will benefit from these low emission properties. Because one mix ratio satisfies multiple pieces of equipment, Saber Professional eliminates mix ratio confusion. Saber Professional is recommended for pre-mix where ISO-L-EGD, JASO FC or API TC is specified.

Saber Outboard

Saber OutboardSaber Outboard (ATO) is specifically designed for outboard motors. It is also very good for personal watercraft, jet boats, motorcycles, snowmobiles and ATVs. Saber Outboard contains a heavy dose of lower temperature dispersant additives that excel at preventing varnish and deposits from forming in water-cooled motors. Saber Outboard is a very low smoke, low odor, low toxicity product that produces as much as 30 percent fewer emissions at 100:1 mix ratios than oils mixed at 50:1. It is ideal for trolling motors as it prevents "oil loading" and plug fouling for rapid throttle response. Operators and the environment benefit from the use of Saber Outboard. It is recommended for pre-mix use where TC-W3 or API TC is specified.


Amsoil Saber 100:1 2-Cycle Oils are recommended for 100:1 mix ratios in normal service and 50:1 to 80:1 mix ratios in severe service applications such as commercial equipment operations and racing.

HP Injector Synthetic 2-Cycle Oil

HP Injector Synthetic 2-Cycle OilNew Amsoil HP Injector Synthetic 2-Cycle Oil is a precise synthetic formulation that exceeds the lubrication demands of modern two-cycle engines. It contains premium synthetic base oils and MAX-DOSE additive system, providing superior performance in direct fuel injected (DFI), electronic fuel injected (EFI) and carbureted outboard motors, as well as other recreational two-cycle equipment.

  • 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

HP Injector is a precise synthetic formulation that exceeds the lubrication demands of modern two-cycle motors. Today's two-cycle 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.


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.

Two-cycle Engine Applications and Lubrication Needs

Two-cycle engines can be found nearly everywhere these days. They are used in dozens of applications and in a wide variety of designs for everything from work and recreation to power generation. Two-cycle engines have design differences and operate under conditions that require different oil chemistries than their four-cycle counterparts. In order to recommend a lubricant for a two-cycle engine, one needs to know how this engine operates, why it is used in place of a four-cycle engine and where and in what type of applications it is used.

What is a two-cycle engine?

What is a 2-cycle engine?

Two-cycle motors deliver one power impulse for each revolution of the crankshaft.

The terms "two-cycle" and "two-stroke" are often inter-changed when speaking about two-cycle engines. These engines derive their name from the amount of directional changes that the pistons make during each power stroke. Internal combustion engines are used to produce mechanical power from the chemical energy contained in hydrocarbon fuels. The power-producing part of the motor's operating cycle starts inside the motor's cylinders with a compression process. Following this compression, the burning of the fuel-air mixture then releases the fuel's chemical energy and produces high-temperature, high-pressure combustion products. These gases then expand within each cylinder and transfer work to the piston. Thus, as the engine is operated continuously, mechanical power is produced. Each upward or downward movement of the piston is called a stroke. There are two commonly used internal combustion engine cycles: the two-stroke cycle and the four-stroke cycle.

How are two-cycle engines different from four-cycle engines?

How is a 2-cycle engine different from a 4-cycle engine?A four-cycle engine requires four strokes of the piston (two up and two down) and two revolutions of the crankshaft to complete one combustion cycle and provide one power impulse.

The fundamental difference between two-cycle engines and four-cycle engines is in their gas exchange process, or more simply, the removal of the burned gases at the end of each expansion process and the induction of a fresh mixture for the next cycle. The two-cycle engine has an expansion, or power stroke, in each cylinder during each revolution of the crankshaft. The exhaust and the charging processes occur simultaneously as the piston moves through its lowest or bottom center position.

In a four-cycle engine, the burned gasses are first displaced by the piston during an upward stroke, and then a fresh charge enters the cylinder during the following downward stroke. This means that four-cycle engines require two complete turns of the crankshaft to make a power stroke, versus the single turn necessary in a two-cycle engine. In other words, two-cycle engines operate on 360 degrees of crankshaft rotation, whereas four-cycle engines operate on 720 degrees of crankshaft rotation.

Where are two-cycle engines used?

Two-cycle engines are inexpensive to build and operate when compared to four-cycle engines. They are lighter in weight and they can also produce a higher power-to-weight ratio. For these reasons, two-cycle engines are very useful in applications such as chainsaws, Weedeaters, outboards, lawnmowers and motorcycles, to name just a few. Two-cycle engines are also easier to start in cold temperatures. Part of this may be due to their design and the lack of an oil sump. This is a reason why these engines are also commonly used in snowmobiles and snow blowers.

Amsoil SnowmobileBecause two-cycle engines can effectively double the number of power strokes per unit time when compared to four-cycle engines, power output is increased. However, it does not increase by a factor of two. The outputs of two-cycle engines range from only 20 to 60 percent above those of equivalent-size four-cycle units. This lower than expected increase is a result of the poorer than ideal charging efficiency, or in other words, incomplete filling of the cylinder volume with fresh fuel and air. There is also a major disadvantage in this power transfer scenario. The higher frequency of combustion events in the two-cycle engine results in higher average heat transfer rates from the hot burned gases to the motor's combustion chamber walls. Higher temperatures and higher thermal stresses in the cylinder head (especially on the piston crown) result. Traditional two-cycle engines are also not highly efficient because a scavenging effect allows up to 30 percent of the unburned fuel/oil mixture into the exhaust. In addition, a portion of the exhaust gas remains in the combustion chamber during the cycle. These inefficiencies contribute to the power loss when compared to four-cycle engines and explains why two-cycle engines can achieve only up to 60 percent more power.

How are two-cycle engines lubricated?

Two-cycle motors are considered total-loss type lubricating systems. Because the crankcase is part of the intake process, it cannot act as an oil sump as is found on four-cycle engines. Lubricating traditional two-cycle engines is done by mixing the oil with the fuel. The oil is burned upon combustion of the air/fuel mixture. Direct Injection engines are different because the fuel is directly injected into the combustion chamber while the oil is injected directly into the crankcase. This process is efficient because the fuel is injected after the exhaust port closes, and therefore more complete combustion of fuel occurs and more power is developed. Direct injection engines have a higher power density than traditional two-cycle engines. Because the oil is directly injected into the crankcase, less oil is necessary and lower oil consumption results (80:1 range). Direct Injection motors have higher combustion temperatures, often up to 120°F. They also require more lubricity than traditional two-cycle motors.

Wanderscheid Continues Winning Ways

P.J. Wanderscheid in Garrision, MinnesotaSauk Centre, Minn. ~ Team Amsoil/Arctic Cat oval ice racer P.J. Wanderscheid was in Garrison, Minnesota, over the weekend. Wanderscheid took third in two Pro 600 Open finals on Saturday, and finished the weekend with the win on Sunday.

The first final was a make-up race from Wausau, Wis., that was cancelled a week earlier due to weak ice. Wanderscheid finished the 10-lap final behind Jim Schmidt and Terry Wahl. The Garrison final started, and finished, much like the one before it. Wanderscheid and Schmidt had nice hole-shots, with Wahl right behind them. Wanderscheid finished the race in third, a good finish after losing a heat exchanger about two-thirds of the way through.

Wanderscheid started Sunday’s Champ 440 final with another strong hole-shot, but was pinched in the first corner. After Wanderscheid came out in fifth and climbed to third after five laps, Wahl’s sled went down and he pulled off. Gary Moyle took the lead until he lost control with three laps to go. After the red flag and the restart, Wanderscheid exchanged the lead with Chris Hortness a couple of times until Wanderscheid took it for good, winning with a half a straightaway lead.

“I’m very happy with the performance and durability of our sleds this year,” said Wanderscheid. “Our sleds are not only showing that we are fast this year, but as the tracks deteriorate, our handling gets better.”

Team Amsoil/Wanderscheid Racing will be in Garrison again this weekend, February 11 and 12. The race has been relocated there from Park X in Hill City, Minn.

The 22-year-old Wanderscheid is one of only three people who have won the illustrious Eagle River World Championship three times. Wanderscheid picked up his third title in 2006.

If you would like more information one Amsoil products, how to become a dealer, or if you would like to buy Amsoil please contact us at: or 419-396-6201, Monday through Friday, 9-5, and Saturday, 9-3.

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