Instruction manual
9
Fuel
This engine requires a mix of 20:1 gas to oil 
lubricant ratio for break-in and a mix of 32:1 
gas/oil ratio for normal operation in order to 
last a long time.
The needle bearing at the bottom end of the 
conrod depends upon this lube ratio to operate 
properly. 
Do not go leaner than a 20:1 gas/oil ratio 
for the first gallon of fuel. After this you may 
decrease the oil content to a 32:1 gas/oil ratio 
if desired. Do not go leaner than a 32:1 gas/
oil ratio or the warranty on your engine will be 
voided.
To properly mix the fuel, for a mix of 20:1 gas to 
oil, add 6.75 oz of good quality 2-stroke oil to 
one gallon (or 53 mL of oil to one liter) of 87–93 
octane fuel. (EVOX1001Q Evolution 2-stroke oil 
is recommended) We prefer to add the oil first 
to our fuel container and to add the gasoline 
second. This helps to ensure a good mixture of 
the oil with the fuel at the outset. 
We have tested our own Evolution 2-stroke oil, 
Valvoline, Shell, RedLine and Husqvarna oils. 
Other quality 2-stroke oils should work as well.
Fuel Delivery System
It is very important to properly construct your fuel supply system to the engine to avoid 
operating problems. Our experience has shown that many seemingly engine related operating 
problems are in fact fuel delivery problems, not engine related problems. 
Fuel Filtering - Because of the incredibly small 
amount of fuel that is being used by this 
engine, filtration of the fuel is mandatory in two 
different spots in the system:
1.  Between the fuel jug and the tank.
2. Within the fuel tank itself (with a sintered 
plastic filter clunk EVOA121).
One of these filters is included with your 
engine.
Tank Location - Because there is a crankcase 
pressure-driven pump on the carburetor, tank 
location is less critical than with a muffler 
pressure-driven system; however, it is still 
good practice to mount the fuel tank in line 
with the carburetor, and as close to the rear of 
the engine as possible. 
Care taken in mounting the tank as 
described will provide trouble free operations 
in all flight attitudes.
Tank Choice and Construction - Choose a tank 
between 8–14 oz (240–420 mL). These tanks 
will yield 12 minutes (for the smaller tank) to 
25 minutes (for the larger tank) of full throttle 
flying time. 
• Ensure you use a tank stopper made for use 
with gasoline and/or smoke oil. 
• We suggest a three-line tank system; one 
for the line to the carburetor with the clunk 
attached internally, one for the vent line 
to the atmosphere, and one dedicated to 
fueling/defueling the tank. We try to avoid 
the T-fittings and other inline valves because 
they can be a possible source of air/fuel 
leaks.
Filtered Weight
Gasoline-resistant Rubber Cap
Fuel Tank Vent Tube
Fueling/De-Fueling Tube
Gasoline-resistant Tube
Carb Nipple
• Ensure you use the included sintered plastic 
filter clunk inside the fuel tank.
• Ensure there is a good seal system for the 
dedicated fueling/defueling line. We highly 
recommend the HAN116 Fuel Filler Assembly 
for its sleek look and ease of use when 
installed on your airplane.










