I have an older MD6A.
I have started it with the hand crank. Things that make this engine easy to start with hand crank is that it has a large, heavy flywheel and it has a decompression lever.
With the decompression lever lifted, the flywheel spins easily. So with the engine ready to start, you start cranking and get the flywheel spinning as fast as you can.
Then flip the compression lever down. All the energy you just spun into the flywheel now goes into starting the engine.
If you don't have those two things I think it would be harder to start.
What if you use the starter with the weak batteries AND you crank too at the same time?