Quote " I rotated the cap a slight bit more, and was able to get it to fire up. It took about 15 seconds with the starter going and it trying to catch." End quote
A couple of times you have alluded to "maybe its low compression".
The described symptom above, while it can be many things, is a classic example of trying to start an engine with low compression. Also, an engine with low compression will take longer to warm to normal temperature, and may need to be run at a high idle for an extended period to warm. A compression test may (or may not) prove interesting. But once and for all a compression test would confirm/deny good compression.
Jerry's method of finding TDC is a tried and true method. Basically, you put an engine stop in the spark plug hole of number one cylinder (the bolt). It needs to protrude in the cylinder lower than the top of the piston. Then, as you assumed, slowly, turn the engine by hand, not with the starter clockwise until it contacts the bolt and make your mark. Now, reverse the direction of the rotation of the engine turning slowly until the engine stops. Make your second mark. As Jerry stated, TDC will be exactly half way between the two marks. If mathematics is your forte, you are approaching a limit from opposite directions.
If you really wanted to prove this, after the first two tests/marks, you could reposition the stop higher in the cylinder, rerun the tests, and the two marks would be closer together. Continuing to reposition the stop slightly higher would eventually have the two marks adjacent to each other (the exact midpoint from the first two tests).
Stay with it.
Jon.
