Fuel System
IMPORTANT
Because this is a gasoline engine, your fuel system (fuel tank stopper assembly, fuel lines, filters, fuel va lves,
etc) much be designed for use with gasoline. Do not use accessories designed for use with glow fuel - no
silicone-based materials.
The Magnum 46cc gasoline engine uses a Walbro carburetor with an integrated fuel pump. For this reason, the
location of the fuel tank is not critical. The pump will draw fuel into the carburetor regardless of the location of the
fuel tank. For best aircraft performance we suggest installing the fuel tank over the models C/G so that no trim
changes will be necessary as the fuel quantity lowers in the tank.
The engine will burn approximately 1oz. - 2oz. of fuel per minute, so we recommend using no smaller than a
24oz. fuel tank. This will result in about 15 minutes of flight time.
Optional Smoke System
A 6mm hole has been drilled, threaded and plugged in the left side of the crankcase to drive an optional smoke
system using crankcase pressure.
Propeller Installation
IMPORTANT Before installing the propeller it must be properly balanced. Running your engine using an out-of-
balance propeller can lead to excessive vibration, which will result in excessive stress and wear on both the
engine and the airframe.
Balance the propeller using the method recommended by the propeller manufacturer. Several products are
available at your local retailer for more information about these items.
Using a 3/8" drill bit or a prop reamer, enlarge the hole in the propeller hub to fit the crankshaft. The diameter of
the crankshaft is 3/8". Slide the propeller onto the crankshaft, up against the flywheel. Slide the propeller washer
up against the propeller and thread the prop nut into place. Adjust the propeller so that one blade is at the 2
o'clock position when the piston is just below top dead center. Tighten the prop nut firmly to secure the propeller
in place.
When tightening the prop nut, use a large adjustable wrench. Do not use pliers.
WARNING
If you are installing a spinner onto your engine, the cone of the spinner must not rub against the
propeller. Allowing the spinner cone to rub against the propeller could lead to propeller damage and eventual
propeller failure.
Propeller Recommendation
The diameter and pitch of the propeller needed for the 46cc gasoline engine will vary greatly depending on the
application the engine is used in. The weight, drag and the type of model and how you intend to fly it are all
factors in determining the correct size propeller to use. Experimentation will be necessary to find the optimal size
propeller for your particular application. Ideally you want a propeller that the engine will turn in the 6,500 - 7,500
rpm range on the ground, yet power the airplane sufficiently. Using a propeller that is too small will cause the
engine to run at too high an rpm. Using a propeller that is too large will cause the engine to run at too low an rpm
and cause it to lug down too much. In both instances this can lead to erratic engine performance, premature
engine wear and eventual failure.
Propeller Size Recommendations
18 X 8 ~ 20 X 10
Fuel Recommendation
T
he fuel used in your 46cc gasoline engine should be high-octane (89 or 91) premium unleaded gasoline mixed
with a high-quality synthetic two-cycle engine oil (
COOL POPWER BLUE
) at a ratio of 30:1 for the first hour of
run-time and a ratio of 50:1 thereafter.
Propeller, Fuel & Spark Plug
