Small Engines (Lawn Mowers, etc.): Craftsman mower oil leak on deck, blown head gasket, head bolts

Question
The Sears mower (model 143.046702, displ 195 cc) is leaking oil from the bottom part of the engine on to the deck.  I checked the breather valve after taking off the flywheel and it does not leak there.  

Please advise what should be done.  Appreciate your experienced help.
Thanks much.

Engine is Tecumseh model LV 195EA.  This mower is about 6 years old.

Answer
Pradipta

It could be a number  of things a blown head gasket,the seal may be leaking from the bottom you could also have a valve gasket leak. The lower part of the engine is often called the oil pan, sump or lower engine case.  These engines are not prone to leaking oil around the sump but it can happen.  Are you sure the head gasket it not leaking?  It is more common for these engines to have loose head bolts which could cause a small leak.

If you have to remove the sump you need to wash the engine and sand the crankshaft to remove all dirt/debris and rust.  With the engine starter sitting on bottom, i.e, the engine upside down, you can remove the sump.  If you are careful the cam and oil pump will not move.  No need to take these parts out.  If you have to replace the gasket, that is removing the sump, I would replace the lower main oil seal.  PVC pipe make a great seal driver.  Pay attention to the depth of the old oil seal before removing so you know how far to drive the new seal.