Lack of leaks is more important than actual pressure. You could try putting some very thick oil in the cylinder and see if the pressure increases, in that case the rings would be leaking. Some more questions:
How are you turning the engine over to start it, by hand or with an electric drill or similar?
Is the sparkplug getting wet with fuel?
Have you done a basic check of the timing in case something has slipped? Turn the engine slowly by hand and check the sequence of events:
Top dead centre, exhaust valve just closing and inlet valve just opening.
Bottom dead centre, inlet valve closing.
Top dead centre, Spark plug should spark.
Bottom dead centre, exhaust valve exhaust valve opening.
If you are turning the engine with a drill or similar close the needle valve completely, start turning the engine and then slowly open the valve.