On the lower unit, find the shift shaft. I assume you already know where it is because you're getting stuck on it
grab a pair of pliers or similar, protect shaft with a rag if you wish and rotate. Rotating it you will find it has 3 positions which is will pop into as you rotate, these are reverse forward and neutral. I forgot which direction is which gear but easy to figure it out by turning prop, neutral prop spins both ways, forward is locked one way spins the other and reverse is locked both ways. Now, rotate lower unit shift shaft into forward, it will pop in and then if you continue to turn freely if you continue rotating it, you want to leave it just where it pops in and no further. Now, put the forward controls into forward also if they aren't already and throw her up making sure you also align the water tube.
Rotate flywheel any way you like, one such way is to use you're manual pull start rope, another is to get a socket and ratchet and place on a flywheel bolt and attempt to tighten it. Another option is to push the prop the way it is locked this will rotate the driveshaft and more of a 1 person method.
I hope that makes sense !
P.s when I say locked this is only the case when lower unit is attached, replace locked with driveshaft spins if that makes sense
