Evolution Engines EVOE20GX - Manual (Page 4)

EN
4
Introduction
Congratulations on your purchase of one of the exciting new engines in the Evolution ® small
block gas engine series. All of the Evolution brand gas engines are designed from the start to
provide you with excellent performance at a fraction of your previous operating costs. We have
painstakingly designed and tested each engine to ensure a hassle-free experience without giv-
ing away anything in expected performance or durability. This manual, when read and followed,
will guide you through the simple steps to your success. Welcome to the Evolution family.
Small Block Gas Engine Design
Starting with our already proven glow engines enjoyed by thousands around the world, we en-
deavored to take that excitement and experience into the realm of gasoline fuel to provide you
with a complete package; great performance and low cost of operation.
Step 1 Start with a great engine. The Evolution glow engines have provided thousands of users
excellent performance.
Step 2 Design a new carburetor system that will be reliable and provide for hassle-free use by
the owners. This new carburetor, with already proven technology, was modified to fit in
the available space in front of the cylinder and the unique needs of a gasoline fueled
engine. Built on to the front of the carburetor is a crankcase pressure-driven regulator
system. This system takes fuel from a muffler pressurized tank and meters it properly in
all attitudes of flight. A new cat’s eye style fuel metering system was added to allow for
more controllability to the low and mid-range throttle positions.
Step 3 Design the proper muffler system to handle the extra heat and expansion of the burnt
gas mixture when compared to a glow system. These changes included adding volume to
the muffler, and enlarging the outlet of the muffler to minimize backpressure while still
providing noise reduction.
Step 4 Design operating accessories that enhance the user experience. During our extensive
2 1/2-year testing program, we discovered a lot of new techniques and obstacles that are
unique to gasoline fueled small block engines.
• Because the amount of fuel consumed is one third that of a comparable sized
glow engine, the construction and reliability of the fuel delivery system to the
carburetor becomes three times as critical. Microscopic pieces of dirt that used
to safely pass through the larger fuel passages of a glow carburetor will wreak
havoc on a gasoline system. By using a quality inline filter like our Inline Filter
(EVOA105) we can take care of the dirt problem. One of these is included with
your engine.
• The same holds true for air bubbles from the tank or any small leak in the fuel
tubing; what would pass harmlessly through a glow carburetor simply is not tol-
erated in a gasoline system because the air bubbles are effectively three times
the size they used to be. We have developed and sourced an excellent felt filter
clunk that, when used in the tank, stops all the air bubbles from moving into the
fuel delivery tubes. This felt clunk is critical to successful and reliable operation.
One of these is included with your engine.
• We found that high muffler temperatures would destroy normal Tygon ® tubing
(the go-to choice for gasoline engines) within minutes. We found that Neoprene
tubing could withstand the temperatures, tended to degrade quickly in use. We
sourced the proper sized fluoroelastomer (FKM) tubing (Gasoline Fuel Tubing
EVOA104), which withstands not only the high temperatures, but its durability
is much greater than that of either Tygon or Neoprene. The added bonus is that
it fits and holds well to the fuel fittings without any need for additional wire or
tie-wrap keepers. We have included a supply of this tubing with your engine.