The SmartCarb SC2 is the culmination of more than 50 years of development. Its pedigree comes from a long line of single-circuit, flat-slide carburetors, including the Lake Injector, Pos-a-Fuel, Lectron (How Do They Compare?), Ei Blue Magnum, and Quicksilver.

The SmartCarb combines the best features from earlier flat-slide, variable-venturi carburetor designs and incorporates design features developed by SmartCarb Fuel Systems, making it a real world solution to satisfying emissions regulations and OEM performance requirements in small engine applications worldwide.

We are currently focused on the off-road 2-stroke and 4-stroke powersports market, offering 25, 28, 36, 38, and 40mm SmartCarb sizes. Application driven development is underway, most recently involving testing for integration in UAVs, mini-motocross bikes, alcohol junior dragsters, micro-sprint carts, snowmobiles, paragliders, and outboard marine engines. The SmartCarb has proven itself to be viable in leisure and competitive applications and is capable of competing directly with electronic fuel injection for both passing emissions regulations and meeting performance requirements.

How the SmartCarb Works


The SmartCarb is a precision fuel and air metering instrument that provides extremely fine fuel atomization, precise air/fuel mixture control, and ambient air density compensation. All of these innovative features are delivered in the format of a single-circuit, flat-slide, variable-venturi, jet-less carburetor.


Superior fuel atomization occurs via proprietary venturi features designed to concentrate and accelerate airflow past a metering rod. This makes for a very high signal at the metering rod, producing fuel droplets that are smaller and more highly atomized than those produced by modern EFI systems and other conventional carburetors. The benefits of fine fuel atomization include:

  • INCREASED POWER. The SmartCarb provides up to 10% more horsepower spread over a broader power curve when compared to competing systems.
  • INCREASED FUEL ECONOMY. Testing shows and customer feedback confirms an average of 30% increased fuel economy. Superior fuel atomization provides for a more complete and significantly cleaner combustion burn, resulting in increases of both power and fuel economy.
  • REDUCED EMISSIONS. The SmartCarb reduces emissions by as much as 50%. By highly atomizing fuel prior to combustion, more of the fuel is consumed during the combustion process, resulting in net emissions reductions. The SmartCarb has twice received North American EPA Tier II and CARB certifications, notably without requiring the use of precious metal catalysts.


Ambient air density compensation is accomplished by the floatbowl pressurization scoop located in the top of the venturi. The scoop allows the venturi to communicate directly with the floatbowl. This means that atmospheric pressures within the venturi are communicated through the scoop to apply pressure on the fuel in the floatbowl. The constant, yet continuous communication and equalization of pressures between the venturi and the floatbowl provides efficient air/fuel mixing within the SmartCarb, regardless of changes in altitude, air temperature, humidity, or other changes in air density. Benefits provided by the floatbowl pressurization scoop include:

  • ALTITUDE COMPENSATION. Successful altitude compensation was initially proven at the Pikes Peak International Hill Climb, with multiple SmartCarb equipped racers taking top spots in 2011 and 2012. The SmartCarb has also been chamber tested by Northwest UAV to simulate altitudes of up to 22,000 feet, again proving capable of maintaining ideal air/fuel ratios regardless of air density changes.
  • NO POWER-JET. The floatbowl pressurization feature helps to drive fuel flow within the SmartCarb, especially when operating at higher throttle positions and venturi velocities when engine demand for fuel is high. This eliminates any need for a power-jet and makes the SmartCarb the only true single-circuit carburetor available today. In fact there are no jets at all!
  • INTERNAL VENTING. Because the SmartCarb is internally vented, meaning it does not vent to atmosphere like conventional carbs, there is no need for overflow hoses. As a result, the SmartCarb does not spill fuel onto the ground. The needle & seat and Technology Elevated patented check-valve system work together to keep the fuel in the floatbowl, even when turned upside down!
  • FURTHER EMISSIONS REDUCTIONS. The SmartCarb is the only mechanical fuel delivery system that is able to meet forthcoming regulations on evaporative emissions. Since the SmartCarb is internally vented, it emits far less evaporative emissions than conventional carburetors do. In fact during certification testing the SmartCarb produced the lowest evaporative emissions ever tested in a carb.


The SmartCarb is incredibly simple to operate and maintain. There are only two adjustments and both can be made by hand, externally, without the need for special tools, and typically without even having to get off the vehicle!

  • CLICKER ADJUSTER. The Clicker Adjuster (on top) is used to raise or lower the metering rod independently of the slide, effectively adding or subtracting fuel flow.
  • IDLE SET SCREW. The Idle Set Screw (on the side) is used to adjust airflow through the SmartCarb at idle and sets idle RPMs.

Making mixture adjustments is as simple as turning the engine off, opening the throttle all the way, and pushing down and twisting the Clicker Adjuster to make fine mixture adjustments and because the SmartCarb compensates for ambient air density, once the right setting is found it can be left alone. No more messing around with jets!


SmartCarbs are proudly made in the USA with quality construction and premium components such as stainless steel fasteners, Garlock gaskets, and high-grade brass fittings. Ergonomic, manually operated chokes and floatbowl drains come standard on all models. Few moving parts and a small part count make the SmartCarb durable and easy to maintain. It truly is the most advanced mechanical fuel system available today.