I always check the oil before every mow. OK I will smell the oil for gas. come to think about it the oil doe's appear to be a tad thiner.
this reminds me of the Yamaha outboard engine they have a term called making oil but I think water is being added to oil.
next mow in a couple weeks I'll take a close look down the throttle plate of carb. an report back.
when you say clean are you say to clean cylinder head fins? thanks Slomo