Small Engines (Lawn Mowers, etc.): Replacing broken piston rod, piston rod, fuel contamination

Question
I have a troy-bilt walk behind mower with a 9HP engine. model 28B702 type 1143-E1

I am looking for some information on replacing a broken piston rod.

A little history...

At one point, it was leaking fuel into the oil, I eventually tracked it down to some crud blocking the needle in the carb. Drained and replaced the oil and fuel. Ran it for about two hours during which is ran great and then as I was mere seconds from finishing, it made a large clank and an abrupt stop.
Eventually, got brave enough to tear the engine down and discovered that the piston rod had shattered. May have gotten overheated from some remaining fuel contamination, I don't know, but I digress. Other than the piston rod, everything looked fine. I ordered a new piston rod, gaskets, and oil flinger. However, as I reassemble it, when I tighten down the piston too the crankshaft, I cannot get it to turn any more. I don't see an remnants of any type of bearing and did not see one in the exploded view. Connections on the old rod pieces so not show any spacers or shims. It would seem like I shouldn't leave any play in this connection, but it is the only way I can get the shaft and flywheel to turn.

What am I missing, do I need to grease the crankshaft? If so, with what?
Or is there some type of adjustment or shim I should be using? Once I get past this, I think I can make a full repair or an stunning conversation piece.

Answer
First you have to verify that there's proper clearance between the rod and crankshaft.  The best way is to use a micrometer and take several measurements around the crank journal and the rod then subtract the difference and see if it falls within spec.  Alternatively you can use Plasti-Gage, just follow the label directions.  

In the best of worlds the crank would have been measured before ordering parts to establish if it's any good and what size rod end you would need.  Often the crank will not be round enough requiring either turning or replacement.  

There's no bearing inserts on most small engines until you get into the larger Honda's.  Let me know if you have any questions, thanks, PK.