Hi Max,
Much thanks for the reply - that does make sense.
Curious thing is though I've run the air filters as is for 5yrs or so without this occurring. This all seemed to start at the last oil change - which again is an odd thing as I've been using this 4-stroke oil combo blend for several years without issue.
The ONLY thing that was different at the last change was I added some Liqui Moly Ceramic engine oil additive when I did the change.
Just mowed another section now and is giving dark smoke more noticeable than ever - will do your carb adjust - if that does not amend I might dump half the current oil in the mower and top up with fresh. It's possible I added a tiny bit too much of the additive when I did the change, so perhaps it's a tad thin now with it's addition.
FWIW the Honda recommended oil for the engine is 10W-30 - so the combo oil should not be far off that.
