Flange Cover/Crank Shaft Question

After replacing the flange cover on a LEV120 shouldn't I be able to hand turn the crank shaft? This is my first time doing this, so I have no idea what's expected.
 
Before reassembly I applied a light coat of engine oil to the cylinder wall and other internal parts including the oil seal on the flange cover. Without the flange cover on I can hand turn the crankshaft. I am aligning the camshaft and oil pump/slinger in their slots as I place the flange cover back on and with a little jiggling the flange cover seats fully. But once in place, without even fully tightening the flange cover bolts, I cannot hand turn the crankshaft. Is that normal, and if not, what might I be missing? 
 
Thanks

Thanks. Good suggestion and I really appreciate the help!

What I found was that one of the valve lifters (tappets?) had moved forward and was not in the right position when I put in the camshaft. With the valve lifters still removed but the camshaft in and the flange cover back on I can turn the crankshaft... so that's good. There is end play but it does seem to get a bit stuck and needs some muscle to get it to move again.

When you say "side cover gasket" are you talking about the flange cover gasket or something else? I was hoping to just be able to use silicon gasket maker for the flange cover instead of buying a gasket.

Thanks again for taking the time. It's a vertical shaft LEV120-362003A 6.5HP from a 2003 Toro mower. I don't mind spending some $$ on it because I want to learn this stuff and this is a perfect opportunity. When the water meter cover popped up and the blade hit it, oh wow. Bent the crank shaft, big crack on the sump, and sheered the flywheel key. 
 
I bought a crankshaft and sump used off of eBay. The sump might be from a different model year than mine, I noticed minor differences in the governor gear, but everything else is the same. The issue I've seen with the hard to turn crankshaft once the sump is on is bothering me. Even after I got everything lined up right internally, once I put the sump on, I can turn it, but it takes some force, I wouldn't say it turns "freely", and there is no end play at all.
 
So, I went ahead and ordered a new sump and gasket (from Jacks!). Once I get those I will start again. 
 
At this point my questions are 1) with everything assembled, no spark plug installed, and the sump bolts only hand tightened should I be able to turn the crank shaft fairly easily just using my hand? 2) Should the sump I ordered come with the governor gear? That doesn't seem like it's something that can be removed/replaced. Also, not sure if it comes with a lower seal, but I have a new one of those, so no problem if it doesn't.


Thanks again.