UMS 5-55 cc, User Manual

Page: 9 / 16

9
Engine Tuning
The break-in settings for the carburetor needles are:
High-speed needle: 1.75 to 2 turns open
Low-speed needle: 1 1/4 turns open
Use a tachometer to tune the engine based on RPM.
WARNING:
Always adjust the carburetor
from behind the propeller. Keep all loose
items away from the propeller at all times.
Never reach over or around the propeller.
3. Fill the fuel tank with fuel.
2. Check the valve clearance, adjust suitably as per the instruction in the
maintenance procedure (Page 11)
4. Make sure the fuel lines are properly connected to the carburetor.
5. Switch off ignition, turn the propeller with closed choke flap until the fuel reaches
the carburetor
6. Switch on ignition and holding the propeller firmly, turns the propeller 2-3 full times
to such fuel into the engine.
7. Now with firm flick, try and start the engine.
8. Engine run approx. at 1000 rpm for two minutes to warmup
1. Use a high quality gear oil to lubricate the outer parts of the valve train at the
beginning of each flying day (WD40 / Liquid Moly Additive)
Starting the Engine
accumulate excess fuel or oil either in storage or during the priming process. Before
beginning the starting process be sure to:
1. Rotate the propeller by hand. During the rotation, if you encounter a point where there is
serious resistance to the rotation, STOP. This is an indication of a flooded cylinder and what
you are feeling is hydraulic lock. Any further attempts to force the rotation of the engine can
result in damage to the cylinder or conrod.
2. If you encountered hydraulic lock, remove the spark plug from the lower two cylinders
and the engine should rotate freely. Continue to rotate until all the excess fluid has been
removed from the cylinder.
3. Reinstall the spark plug and continue with the starting process.
Because of the nature of radial engines, it is not uncommon for the lower cylinders to
Checking for a Flooded Cylinder