Evolution Engines 20GX 20cc - Manual (Page 9)

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.