Instruction manual

engine may die. Be sure to allow the engine to warm up
at idle for a few minutes before conducting normal oper-
ation.
TIPS FOR EXTENDED ENGINE LIFE
To extend the life of your Zenoah engine, the following is
recommended:
1. Use a high quality 2-stroke oil mixed at 32 to 1.
2. Use the recommended spark (glow) plugs.
3. Use the proper propeller size and balance the propeller
prior to use.
4. Always adjust the engine to a slightly rich setting.
5. For Glow engines, use an “after-run” oil when you’re fin-
ished flying for the day.
6. For long-term storage, make sure there is no fuel left in
the tank or the engine. Remove the spark (glow) plug(s)
and apply several drops of high-quality oil (e.g., Marvel
Air Tool Oil) to the top of the engine and into the spark
(glow) plug hole. Rotate the crankshaft several times.
Store the engine in the box it came in or on the airplane
with the nose down in order to keep oil in the bearings.
SERVICING THE ENGINE
Tools Required:
• Regular screwdriver
• Phillips screwdriver
• Hexagonal wrench (4mm
/
5/32”)
• Open wrench (19mm
/
3/4”)
• Plastic hammer
• Thickness gauge
• Tapered round rod
• Liquid gasket (Permatex or equivalent
• Thread lock (Blue Thread Locker Z-42 or equivalent)
• Lithium grease
• Engine oil
• Washing gasoline
• Brush
• Scraper
• Cloth
The engine can be disassembled or reassembled without
any specific difficulties, but note the following:
For disassembling, the special tools shown in the parts list
are required (stopper, puller assembly), in addition to gen-
eral tools. Be sure to use a new gasket when the crankcase
and cylinder have been disassembled.
Note: Because the crankshaft is of the assembly type, do
not disassemble, hit or twist its end.
DISASSEMBLY STEPS
Note: Disassembly and assembly steps were written using
a G-38 engine as an example, but they apply to all engines.
1. Dismount the engine from the model.
2. Remove the carburetor and insulator carefully without
damaging the gasket.
3. Remove the muffler.
4. Remove the spark plug and ignition module. (Note: The
glow engine does not have an ignition module.)
5. Remove the propeller hub.
6. Remove the rotor (flywheel). If it cannot be detached,
use a plastic hammer and hit the part lightly.
a. Screw the stopper in place of the spark plug, then
turn the rotor counterclockwise until the piston touch-
es the stopper. Take care as it can cause damage to
the piston or connecting rod if the stopper is not
screwed in to the bottom.
b. Loosen and remove the rotor securing nut.
c. Remove the rotor by using the puller. Do not hit the
crankshaft with the plastic hammer, as this can
increase the runout of the shaft.
7. Remove the mounting plate.
8. Remove the four bolts from the crankcase.
9.Tap around the case fitting side gently with the plastic
hammer and slowly separate the crankcase from the
cylinder block.
10. Pull out the crankshaft with the piston, bearings, and
other parts attached.
11. Remove the Woodruff key from the crankshaft.
12. Remove the oil seal, snap ring and bearings.
13. Remove the circlip and pull out the piston pin.
14. Remove the thrust washers and needle bearing from
the smaller end of the con rod (G-38).
15. Remove the piston ring.
16. Wash each part. Check for abrasion and damage, and
replace any part that is defective.
ASSEMBLY (G-38)
1. Apply engine oil (SAE #30) to the inside of the cylinder
and to the needle bearings on the larger end of the con-
necting rod.
2. Fit the piston ring to the piston.
3. Mount the needle bearing and thrust washer (with its oil
slot facing inside) to the smaller end of the connecting
rod and apply engine oil (SAE #30).
4. With the arrow on the top of the piston facing the
straight side (opposite side to the propeller) of the
crankshaft, fit the piston to the top of the connecting rod
and insert the piston pin with its blank end to the
exhaust port side.
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