Small Engines (Lawn Mowers, etc.): BS engine leaking oil, crankshaft seal, center bolt

Question
John: I have a 11hp BS vertical shaft single cylinder engine in my lawn tractor that is probably 15-20 years old. It runs great but I find that I have to replace the seal at the bottom of the engine that the shaft goes through almost once a year.  I carefully remove the old one with a pick and install the new one with gasket goop on it. But, they never last. Am I installing incorrectly or is there something else I have to look at.  I have used only genuine BS parts.

Answer
Hello Bob:

The Reason for the Oil Seals Constant Damage and Replacement is in the Instruction File I am Including. I Hope this is the Information you are Requesting. The Following is a Basic Instruction File for Replacing this Seal. Any Input is Appreciated. Remove the Spark Plug. If you Must Tilt the Mower/Engine, then Tilt it so the Plug Hole is Facing Up. Turn the Engine and Watch the Center Blade Bolt as the Engine is Turned. If the Bolt Turns True, then the Crankshaft is Not Bent. If the Center Bolt Wobbles, then the Crankshaft is Bent and this can be the Cause of the Lower Seal Leaking. Depending on How Bad the Crankshaft is Bent will Determine How Often the Lower Seal will have to be Replaced and if the Mower has a Vibration Also. I have Seen Engine that have the Lower Seal Replaced Every Year Due to a Bent Crankshaft. The People Still Operate the Mower, they Just Replace the Seal at the Start of Each Cutting Season. To Replace the Lower Crankshaft Seal; **Remove the Blade and Blade Adapter. Sand the Crankshaft with Emory Cloth Sand Paper and Remove All the Rust and Burrs. The Using  a Small Flat Head Screwdriver, Pop Out the Old Seal. Sometimes, you have to Use a Small Cutting Chisel and Cut the Seal First. I Use Pipe of the Same Outside Diameter of the Seal(Close as Possible) and 3" Longer than the Crankshaft with an End Cap on it. Place the Seal Into the Engine Base and Get it Started. Place the Pipe Over the Crankshaft and Drive the Seal Into Place. Sometimes, if you have a Full Tool Set; you can Use a Deep Well Socket to Drive the Seal Into Place. Make Sure it is Deep Enough to Miss Hitting the End of the Crankshaft.** If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

PS: I am Allowed to Answer 10 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. Ratings and Comments are Greatly Appreciated. Thanks.

Respectfully

John