Small Engines (Lawn Mowers, etc.): Is it worth replacing engine in Crafstman Snow Thrower, oil leaks, snow thrower

Question
Just started my Crafstman Snow Thrower for the year.  Motor stopped, smoked and locked up.  Will not start now.  I found what look to be a couple small pieces of flat metal under the unit.  Oil leaks out by the electric starter when I try to start the unit now.

Is it worth replacing the engine.  I bought this in 2001 and the engine model is 143.999001.  I think the engine will be around $350 - $400, but not sure how much labor.

Did I throw a rod or is it something simpler.  Is it worth replacing?

Answer
Jason
I would check first the area of the starter. Try to pull out the starter and see if the starter gears didn't get chewed up this is a problem. This unit may also have a pull starter,or was replaced to the electric starter only. I would check that first. They do not make a replacement engine for this just a short block to rebuild if the the engine is blown,if you need more help let me know