Jordan Pushing down on the crank handle works great to spin up, but unless you are young and large, you will still run into issues getting enough RPM in the wheels where the stored kinetic energy will be high enough to carry you thru the compression stroke unassisted. This is especially true on a new/fresh engine. This only gets worse with the cold! To start these beasts as easy as possible, even when warm, you need to shift to pulling up hard on the handle as soon as you drop the compression release. Since you will most likely be disengaging the compression release while the exhaust valve is open, which happens on an upward pull of the handle. The next downward stroke of the handle is the intake stroke, and the the hard upward pull only needs to be accomplished on the next upward revolution of the handle. It is a sutle timing thing which you will pick up pretty quickly once you start trying to start yours. Look on youtube and wach some being started, and you will probably see what I am talking about since you now know what to look for. The old guys make it look easy, only cranking it up to a moderate speed, but giving one really hard pull after releasing the compression to get that first fire...
With cold bearings and belts, the speed will slow to a point that even a good strong last upward pull won't get it thru compression. You need to warm the bearings to get up to a speed to be able to pull thru by hand. A little heat applied to the bearing carriers and generator end plates makes a huge difference in cranking ease. I use alcohol and propane torch to warm these points, but it has to be done gently and takes time for the heat to penetrate to the bearings without cracking/damaging anything or cooking the crank seals. That is where the electric pony starter really shines. It's near constant crank force more easilly overcomes the drag of cold parts and cold muscle:)