Thanks so much!Hello S.,
I worked as a small engine mechanic back in the late 70's when I first started out. Most parts were kept in stock including overhaul components for the most common brands. It was economical back then to perform a basic overhaul. Now the parts are sky high or no longer available and the labor would easily exceed the cost of a new engine.
It was fairly steady work until later when the OHV (throw away) engines came out, then the bottom dropped out of the repair business. Most engines were not worth the effort to overhaul because many of them would break a connecting rod and punch through the block.
Aside from that most engines are not built to be saved anymore, just ran until they quit or blow up. Manufacturing engineers are creating the perfect disposable engines. Manufacturing loves it because they can sell more equipment and make profits just to add their junk to the salvage piles.