First off, Bill Kapaun
has given you all you should need to trouble shoot the issues. Putting the
in to a reply back to Bill after helping you is taken as an insult, at least to me it is. Nontheless, I'll try to give you a little more advise and see what you do with it.
First and far most you should apologize
You seem to be focused on valve guides, why? From the information you have left in previous postings I believe you are barking up the wrong tree.
More then likely the primary path for oil getting into the combustion chamber is passed the piston rings. You mentioned that the compression was 100 psi. What type of compression test did you run? Was it a motoring test or differential? If it was a motoring test, 100 psi is low. You also mentioned that you could feel air out the breather. Was this with the engine running or motoring or when you did the compression test? Air out the breather vent normally indicates leakage past the piston rings. Bottom line, from way out here in web world, best guess would be worn piston rings.
- do nothing and use the mower with the smoke
- replace the piston rings and hone the cylinder walls (this is assuming the piston and cylinder are ok)
- add heaver grade engine oil (40 or 50).
Best of luck,