Small Engines (Lawn Mowers, etc.): B&S 20HP timing problem, pan gasket, belly pan

Question
My "belly pan" gasket failed and I disassembled the bottom of the motor to replace it.  The Mower is a B&S 406777 20 HP intek twin cylinder.  When I removed the "belly pan", the camshaft was not sitting in its recess and I am sure that I didn't return it to the right location as the mower will not run.  Is there any way to correct this without disassembling the engine?  Once its open, how can I return the camshaft to its correct location relative to the crank?
Thanks for your help!

Answer
First thing you need to do is get a repair manual, one should never attempt this type repair without one. The sump gasket failed due to a dirty air filter, these engines are known for this, if hey can't suck air by way of the filter they will suck the sump gasket in to draw air.   Nope, no way to make the needed timing repair without pulling it a part again. Each has a timing mark that much match up and be aligned. You'll need to refer to the manual for the timing mark diagram......Tom