Small Engines (Lawn Mowers, etc.): Replacement engine for Craftsman ride-on?, nick nick nick, crankshaft size

Question
Cutting the grass this weekend, my 2000(2001?) model 917.270671 w/16HP B&S Intek starts to run louder and slower and eventually dies. I let it cool down, starts, but again - a loud, slow death. Pretty sure it's DOA as I admit I drove it pretty hard these past two years with lots of improper (read - no) maintenance. It's actually on it's second engine as the first gave up the ghost after 2 years.

ANYWAY - I'm looking to replace the engine with a new or good used one. How can I tell what will fit? On the engine it says: MOD 311707  TYPE 0132-E1  CODE 990910ZE but I'm pretty sure these dont mean as much as the crankshaft size and the such (right)? I'm pulling the old engine off today.  

Answer
Nick, Nick, Nick.

2 engines in 7 years, that's a new record.  My guess is that if the engines are getting this much use the rest of the tractor is also about worn into the dust.  Buy a tractor more suited for your level of use.  I have found that ebay is actually a good source for new and used engines.  The crank size and length "are" the crucial things.  You can make any engine fit if it has the right crank and you don,t mind being creative.