>>clean with kerosene every couple of oil changes<<
What did they want you to clean, the paint off of it?
If you want the inside of the engine to stay clean, hook up a good PCV system and change the oil on a regular basis.
I use 30w nondetergent in the compressor, but 5-30 or 10-30 in the mower. My 292 gets Mobil 1, 5-30 on a six year old build.
