I've very recently had some trouble with a push mower I bought last fall. A couple weeks ago, the engine died a couple minutes after I started mowing. Turns out it was out of gas, so I refilled it. However, once it was re-filled, the engine would die within a second of starting again. I put oil in the tank, added some stabilizer (which also has some fuel-line-cleaning additives), and no luck.
I read that this sounded like a carburetor problem, so I took off the bowl and dumped the fuel that I found sitting in there. I had expected to see the jets clogged, but I instead found them completely clear. Disappointed, I put everything back together and gave it another start. This time it ran, and I hoped that this meant that I had just flooded the engine.
Fast forward a couple weeks. The engine runs out of gas while I'm mowing; this time the tank is bone dry. I refuel, add more fuel stabilizer, and it starts just fine, but after a moment, it dies again. After a few tries, it's back to stalling immediately after it starts. I took the carburetor bowl off again, dumped it, and replaced it, but this time it didn't work.
This is Hyper Tough mower with a Briggs & Stratton 300E engine, the kind with an all-plastic carburetor.