Starting The Engine; Engine Tuning - UMS 7-90 cc User Manual

Checking for a Flooded Cylinder
Because of the nature of radial engines, it is not uncommon for the lower cylinders to
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 ooded 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 uid has been
removed from the cylinder.
3. Reinstall the spark plug and continue with the starting process.

Starting the Engine

Use a high quality gear oil to lubricate the outer parts of the valve train at the beginning
of each ying day.
1. Fill the fuel tank with fuel.
2. Make sure the fuel lines are properly connected to the carburetor.
3. Switch off ignition, turn the propeller with closed choke ap until the fuel reaches
the carburetor
4. Switch on ignition and holding the propeller rmly, turns the propeller 2-3 full times
to such fuel into the engine.
5. Now with rm ick, try and start the engine.
6. Engine run approx. at 1000 rpm for two minutes to warmup

Engine Tuning

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.
The break-in settings for the carburetor needles are:
High-speed needle:
Low-speed needle:
Use a tachometer to tune the engine based on RPM.
2 turns open
1 1/4 turns open
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