Ok, after reading from beginning to end it sounds like you adjusted the valves when the motor was on exhaust stroke instead of compression stroke.
Forget everything you know about 2 strokes for a minute.
On a four stroke the cam turns half as fast as the crank. So it takes two full revolutions of the crank to complete all four strokes. What this means is that the piston comes to "tdc" (next to the "f" mark) twice in one combustion cycle.
If you did not have it on the compression stroke when you adjusted your valves then they are way too loose because they were partially open during exhaust stroke when you set the gaps.
To tell where you need to be remove plug and place finger over hole while rotating engine. When the piston comes to "tdc" on the compression stroke you will feel it push your finger off. Thats where the engine needs to be to adjust the valves with it lined up at "tdc"
Remember, that an engine fires a few degrees before "tdc". So any "tdc" marks will come after the "f".
Also be damn sure you're rotating the engine in the correct direction. (edited)