Small Engines (Lawn Mowers, etc.): Push mower crank seal, harmonic balancers, seal surface

Question
I have a Sears push mower with a 4.5hp Tecumseh engine on it.  The mower is 11+ years old and runs great.  The only issue is that it just started leaking oil from the bottom seal.  I removed the old seal and installed a new one after cleaning the shaft up with a 3M pad.  To make sure I obtained a good seal, I pushed the seal past any rough pitted surfaces onto a new surface.  I also oiled the seal to keep it from being ruined upon startup.  It still leaks.  I use Amsoil 5W-30 synthetic (probably why it still runs great and doesn't burn oil) and have never had a problem.  What can be done?  I remember from my auto engine rebuilding days harmonic balancers could be fitted with a sleeve to provide a new seal surface.  Is there anything like that for mowers?  Thanks in advance
Dave

Answer
Hello Dave:

I haven't Ever Seen or Heard of the Sleeve Kit like they Make for Autos. Wish they Did. However, I Make a Thin Shim and Place it in the Engine Housing Before I Install a New Seal if there is a Groove in the Crankshaft. All you Require is a .050in Shim and the Seal will Ride on a Different Section of the Shaft and Doesn't Stick Out Far Enough to Put the Seal in Danger of Being Damaged by Debris. If the Crankshaft is Bent the Lower Seal will Leak Also. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

Good Luck

Respectfully

John

Hello Dave:

Have you Looked Into having the Crankshaft Straightened. The Cost is Not Usually that Great if you Remove the Engine from the Deck for the Shop. Hope this Helps. I am here if you Require more Assistance. Thanks.

Good Luck

Respectfully

John