27
Hangar 9 Taylorcraft 26cc BNF
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: 1
1
/
8
plus/minus
1
/
4
b. High-Speed Needle: 1
3
/
8
plus/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.
high-Speed Needle:
Turning this needle clockwise makes
the gas mixture leaner, and turning it counterclockwise
makes it richer. Set this needle at a position which is 1/4
open from the maximum rpm position while the aircraft is on
the ground.
Note
:
Do not tighten the high-and low-
speed needles too tightly.
When the engine has just started and is not warm
enough, there may be insufficient acceleration
and the engine may die. Be sure to allow the
engine to warm up at idle for a few minutes
before conducting normal operation.
Engine Care and Maintenance
Recommendations
To extend the life of your Zenoah engine, the following is
recommended:
1. Use an Evolution® quality 2-stroke oil mixed at 32 to 1
2. Use the recommended spark 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 long-term storage, make sure there is no fuel left
in the tank or the engine. Remove the spark 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
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.
6. Check the muffler bolts frequently to be sure they are
not getting loose. If you heat up the engine and then
tighten the bolts down when hot the bolts will stay
secure longer.
Servicing the Engine
Required Tools
• Regular screwdriver
• Phillips screwdriver
• Hexagonal wrench (4mm, 5/32-inch)
• Open wrench (19mm, 3/4-inch)
• Plastic hammer
• Thickness gauge
• Tapered round rod
• Liquid gasket (Permatex or equivalent)
• Threadlock (Blue Threadlock 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 general
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
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.
5. Remove the propeller hub.
6. Remove the rotor (flywheel). If it cannot be detached,
use a plastic hammer and tap the part lightly.
a. Screw the stopper in place of the spark plug, then
turn the rotor counterclockwise until the piston touches
the stopper. Take care, as it can cause
damage to the piston or connecting rod if the
stopper is not screwed into 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 piston ring.
15. Wash each part. Check for abrasion and damage, and
replace any part that is defective.
