Small Engines (Lawn Mowers, etc.): Toro 521 Snowblower seized up, piston rod, assembly drawings

Question
I told my neighbor that I'd take a look at his dead Toro
521 Snow thrower with a Tecumseh engine.  I'd expected a
fuel or electrical problem, but what I find is that the
engine will only turn about 20 degrees and makes
unpleasant metal banging noises at both ends of its
travel.  I'm guessing a busted piston rod or something of
the sort, but I know next to nothing about snow throwers.  
Is it possible that the problem isn't in the engine but is
in something attached to the driveshaft?  Is there some
usual protocol for troubleshooting problems like this, or
should I just start taking parts off until I find the
problem?

Answer
Hello Don:

>>From your Description, your Diagnosis is Right On as to the Broken Connecting Rod.
>>There is Nothing that would cause the Problem you Described Other than a Broken Connecting Rod Inside the Engine.
>>To Check for this Problem, Remove the Cylinder Head and Watch the Piston while Turning the Crankshaft.
>>You can View a Breakdown/IPL of the Mower at this Site Addy, https://lookup3.toro.com/partdex/default.cfm and Select Start Parts Viewer. Now Enter the Model Numbers () and Click Search. Now Select View Assembly Drawings for your Year Model.
>>**If you Need Assistance in Locating the Model Numbers, then You can Go to this Site Addy; https://lookup3.toro.com/partdex/default.cfm and Select Step 1.**  
>>If you Hit a Snag or this Does Not Correct the Problem,  I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 3 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. All Follow up Questions are Accepted at Any Time. Comments and Ratings are Greatly Appreciated. Thanks.

Respectfully

John