APC Zenoah User Manual
ENGINE INSTRUCTION MANUAL
G26 Air
G26/231 Marine
G231 Heli
G38
G62
GT80 Twin
G45
®
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Table of Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Support Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Mounting the Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Break-In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Starting the Engine-Aircraft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Starting the Engine-Heli & Boat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Stopping the Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Carburetor Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Engine Care and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Servicing the Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Troubleshooting Guide for Gasoline Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Propeller Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Engine Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Exploded Illustration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
G26/G231 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
G38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
G45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
G62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
GT80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Warranty Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Non-Warranty Repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Registration Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
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Introduction
Safety Instructions
Very Important
This manual describes the engine’s features and functions. For specific information on mounting, see the
instruction manual included with the model airplane, helicopter or boat in which you intend to install the engine.
This model engine will give you considerable pleasure,
satisfaction and performance if you strictly follow these
safety instructions and take heed of the warnings as to
the engine’s safe and proper use. This engine has more
than enough power to cause harm if misused or if the
safety precautions are not observed.
Always
1. Use genuine parts for replacement.
2. Check the propeller, rotor (helicopter) or screw
propeller (boat) prior to each time the engine is used.
If nicked, scratched, cracked or damaged in any way,
replace it with a new one.
3. Use the correct size and pitch of propeller for your
engine; refer to the propeller chart in this manual.
4. It is extremely important to balance the propeller
prior to installation of the engine. Failure to do so may
cause damage to the Zenoah engine and/or the airframe.
Securely tighten the propeller nut against the washer
and propeller.
5. Inspect the tightness of the propeller nut prior to
each flight.
6. Keep your face and body away from the path of the
propeller blades when starting or running your engine.
7. Use a thickly padded glove when hand starting
the engine.
8. Make all carburetor adjustments from behind
the propeller.
9. To stop the engine, the black lead wire from the
coil should be grounded to the engine body, or use the
throttle linkage to shut off the air by closing the throttle
valve completely.
DO NOT USE HANDS, FINGERS OR ANY OTHER PART
OF THE BODY TO STOP THE PROPELLER. DO NOT
THROW ANY OBJECT INTO A PROPELLER TO STOP IT!
10. Ensure that all spectators, especially children, are at
least 20 feet away when you start running the engine.
11. Make sure your fuel is kept in a safe place well away
from sparks, heat or anything that could ignite the fuel.
Recommendations
1. Use safety glasses or goggles when starting and
running your engine.
2. Do not run the engine in the vicinity of loose gravel
or sand. The propeller may throw such materials into
your eyes. The engine could also ingest these harmful
materials.
3. Avoid loose clothing when operating your model
engine, as it could become entangled in the propeller,
creating the possibility of bodily harm. All loose objects
(screwdrivers, pencils, nickel cadmium glow drivers,
etc.) should be removed from your pockets so that they
do not fall into the propeller.
Congratulations on purchasing a Zenoah®engine. Cared
for properly, these high-quality, finely crafted engines will
offer many years of reliability.
This instruction manual has been developed to ensure
optimum performance from the Zenoah engine you have
purchased. It’s important that the instructions are read
thoroughly prior to mounting and running the engine.
FAILURE TO READ AND FOLLOW THESE INSTRUCTIONS BEFORE YOU PROCEED MAY RESULT IN ENGINE
DAMAGE AND THE VOIDING OF YOUR WARRANTY!
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Safety Instructions (continued)
Support Equipment
Caution
1. Model engines get very hot while running. Do not
attempt to handle them until they have cooled.
2. Always run your model engines in a well-ventilated
area. Similar to automotive engines, model engines produce harmful carbon monoxide fumes.
3. Never modify the flywheel.
4. Check the flywheel. If it’s damaged, replace it with a
new one.
5. When mixing the fuel or operating the engine, do so
in a well-ventilated area
6. Remember that model engines produce a substantial
amount of power, more than enough to seriously injure
people and/or do considerable damage to property.
Always use common sense, skill and constant observation of safety precautions.
Disassembly
The Zenoah engine can be disassembled or reassembled
without any specific difficulties. Refer to the Engine
Maintenance Section for specific instructions on these
procedures. If you need service to your Zenoah engine,
please send your engine to the authorized service center
at the following address:
Horizon Hobby, Inc.
Attention: Zenoah Service
4105 Fieldstone Road
Champaign, IL 61822
Phone: (217) 355-9511
Engine Parts Identification
It’s important to be able to identify the parts of your
Zenoah engines. Attached you will find an exploded view
of Zenoah engines, as well as a chart including part
numbers and descriptions. This will assist you in easily
and rapidly identifying the respective parts of your
Zenoah engine.
The following items, which are not included with your
Zenoah engine, are necessary in order to operate the
model engine.
Fuel—Mix gasoline and 2-stroke oil at a mixing ratio of
25-40:1.
Note: Be sure to use a gasoline-resistant fuel
tubing (do not use any silicone rubber tube).
Never use any alcohol fuel or alcohol-added
fuel as this will damage the rubber part of
the carburetor.
Propeller—Refer to the Propeller Selection Chart located
on Page 8 to determine the best initial propeller for your
particular application.
Manual or Electric Starter—For manual starts, a
chicken stick is highly recommended. Never use your
fingers to start any model engine as you could get
injured. If you must hand start a gasoline engine, be sure
to protect your hand with a heavily padded glove. There
are a variety of heavy-duty electric starters on the market
that can be used.
Zenoah Oil
ZEN20001
Zenoah Start Kit
ZEN20002
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Mounting the Engine
Make sure the engine is mounted on the aircraft using
aircraft grade plywood that’s at least 6mm in thickness
for the G26 engine, and 10mm in thickness for the G38
through GT80 twin, or a mount of equivalent strength.
Make sure it’s firmly mounted with 4 bolts.
1. Be sure to set flat washers or a metal plate on the
reverse side of the mount to prevent the bolts from sinking into the mount. Periodically check the engine mount
for loose bolts.
2. Since the engine is equipped with a floatless carburetor with a diaphragm pump, the direction of the cylinder
and position of the fuel tank can be freely selected.
3. If the engine is mounted on a shock (rubber) mount
placed between the engine and the firewall for anti-vibration, check the hardness of the rubber, making sure it’s
not too soft, in order to avoid excessive vibration during
engine operating rpms. It’s suggested you note carefully
if the engine is vibrating at idle as excessive vibration
can result in erratic engine operation due to overflow at
the carburetor.
4. It is suggested you coat the bolts for the muffler with
threadlock when mounting the muffler to the engine.
Break-In
No specific break-in is required. The engine is gradually
broken-in as it is used, and the output power increases
gradually as the engine breaks in.
Starting the Engine—Aircraft
Before attempting to start the engine, be sure to read
through all the steps for starting the engine as outlined
below:
Zenoah engines are equipped with the ultra compact
C.D.I. type flywheel magneto ignition system and should
be started according to the following procedure:
Note: The magneto system is timed in such a
way that when the compression stroke starts
(refer to Figure 1-A) sparks are never produced
on the spark plug, no matter how fast the propeller is flipped. The correct starting procedure
is to quickly flip the propeller when the edge of
the magnet on the rotor is approaching the coil
(Figure 1-B). This means that the propeller
should be quickly flipped at about 90 degrees
in crank angle before the compression stroke is
about to start.
1. Make sure the spark (glow) plug(s) are installed and
tightened. Check the condition of the plug cap for cracks
or breaks.
2. Be sure the propeller is properly secured.
3. Make sure the fuel tank line(s) are properly connected.
The main line should be connected to the carburetor
spray bar.
4. Be certain the mufflers are installed properly.
5. Fill the fuel tank.
6. Choke the engine and turn the propeller through a
few times until the fuel appears at the carburetor.
7. Set the throttle valve at the idle position or at the
position slightly open from idle.
Fig 1-A
Coil
Magnet
Fig 1-B
Operation
6
Operation (continued)
8. Quickly flip the propeller in a counterclockwise
direction according to the procedure described in
the note above.
9. The engine should start after a few flips of the
propeller.
10. Be sure to open the choke when the initial firing
of the engine is heard.
11. When the choke is opened, be sure to close the
throttle valve to a position near the idle position before
the next flipping of the propeller is attempted.
CAUTION: If the engine is started when the throttle is wide open, a great thrusting force will be
generated, which can be very dangerous.
12. If you do not use a chicken stick to start the engine,
be sure to wear a thick glove when flipping the propeller
and use all fingers, except the thumb, for the flipping
operation.
13. Do not over-rev the engine. These engines are
designed to develop maximum output with the standard
muffler and the recommended propeller size. Please
refer to the propeller chart on page 10 to confirm the
proper propeller for the applicable Zenoah engine.
Starting the Engine— Helicopter and
Boat
1. Fill the tank with fuel.
2. Push the priming bulb located on the carburetor until
fuel appears in the priming bulb (for helicopter).
3. Choke the engine and open the throttle valve approximately 1/3–1/2 of the full open position.
4. Quickly pull the starter cord until the initial firing of
the engine is heard.
5. When the initial firing is heard, open the choke, set
the throttle valve at the idle position or at the position
slightly open from the idle position and quickly pull the
starter cord a few more times until the engine starts.
6. For helicopter operation, you should adjust the rotorpitch to obtain a 9,000 to 10,000 rpm of the engine at
full throttle operation.
Stopping the Engine
The ability to shut down the engine in an emergency is
extremely important. For stopping the engine, the black
lead wire from the coil should be grounded to the engine
body, or the throttle valve should be closed completely.
Installation of a “stop” or “kill” switch is recommended.
Refer to the example shown in the following diagram.
Carburetor Adjustment
The carburetor is provided with three adjustment screws,
which are factory set to the best (approximate) positions. They may need minor adjustment, depending upon
the temperature, humidity, atmospheric pressure (altitude), etc., of the area where the engine is being used.
1. Start the engine without making any adjustments.
2. Make adjustments only when the engine shows signs
of inefficient operation.
3. Standard settings of each needle is as follows:
a. Low-Speed Needle: 11/8plus/minus 1/4
b. High-Speed Needle: 13/8plus/minus 1/4
Idle Screw: Turning this screw clockwise increases the
idling RPM. Turning it counterclockwise decreases the
idling RPM.
Low-Speed Needle: This is the fuel adjust screw (not
the air screw). Turning this needle clockwise makes the
gas mixture leaner, and turning it counterclockwise
makes it richer.
Red Lead
Black Lead
Kill Switch
Engine
Body
Ground
High-Speed Needle
Low-Speed Needle
Idle Screw
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