Hi Kempe, and a warm welcome back to the forum.
I had a similar problem with my Briggs many years ago, it just became unreliable; would not start when I wanted to go mowing, was blowing a bit of smoke....not a lot...but enough to worry me...I bit the bullet and re-engined the machine with a G100 2.5HP. Honda and never looked back!
Briggs and Stratton are a good engine to work on, but when getting to the end of their working life can be pernickety and unreliable....the hard part is realizing when that time is reached.
