Small Engines (Lawn Mowers, etc.): Tecumseh 5HP engine on snowblower, drive pulley, inopportune time

Question
I have a 5HP Tecumseh engine in my 23 inch Snow Chief snowblower. My father got it at an auction, so there was no manual with it.It worked fine for over a year and then one afternoon during a nasty snowstorm,I pulled the handle and the cord locked up. I have disassembled the pull cord unit and it works fine when disassembled. It appears as the engine (flywheel?)itself has locked up. Any ideas on why it just decided to lock up at such an inopportune time? Thanks!

Answer
I'm not sure if it knew whether it was an inopportune time, however, I can recommend a few things to check before you proceed.  Remove the cover on the opposite side of the flywheel to expose the drive pulley(s) and drive assembly.  If you have to, remove the belts from the engine pulley.  You need to isolate if the problem is with the engine or the driven accessories first.  Let me know what you find.