It's amazing what people discard due to lack of maintenance on their equipment. I have two lawn mowers that were both kicked to the curb, if you will.
One was half taken apart because they were unable to diagnose the problem. It needed a carb rebuild which consisted of a diaphragm, a few gaskets, and a cleaning. I also changed the oil, new plug, and it runs alike a charm.
A few months ago, one of my neighbors was throwing out a Bolens pushmower. It was covered with dirt and grass clippings. I saw it as a challenge. It even had a full tank of gas.
First thing I did was gave it a good cleaning with some Purple cleaner. It looked like brand new. The air filter was clogged with dirt...washed it out, pulled the plug and cleaned that.
It started right up and runs like a champ.
The last time I bought a new mower was over 20 yrs ago. I've since put that one to the curb for someone to take. It was gone within the hour. It still ran too, but was getting tired.
I also found my weed whacker the same way. Bought a carb kit for that, cleaned out the gas tank and lines and it runs fine.