Thanks for the advice. Drained the oil out and nothing came out. The oil fill tube may come off, but typical of this product, it would be very difficult to do. The problem is the red "decorative" plastic surround as it was not made for this MTD engine.
Spoke with service tech at dealer and he suggested trying to get oil fill tube off and I'll try that again, but the top gets in the way. To remove top you have to snap off plastic connecting "bolts" and then take ignition switch and fuel control loose and then remove the seat and disconnect the fuel cap from its tether. So, major labor costs before tech even gets to the engine itself.
Of all the lawn mowers, I have ever owned, this is the dumbest design. Of course the other riders were Snappers. My push is a Troy-Bilt, but it has a Honda engine.
Thanks again for help.