I've got a couple of used self propelled mowers with the same GVC 160 engine. One is a Harmony and the other a Sears. The Harmony was running when purchased, cost $75 and came complete with the rear bag. The Sears was not running but cost $25. I bought inexpensive Amazon sourced carburetors, adjusted valves, changed oil and mounted automotive quality inline fuel filters and they've both run well for the last 5 years.
I run gas treated with Startron year round and generally never have an issue. This spring though, the Harmony started, ran, but leaked from the overflow. I found the needle valve corroded and not sealing. That part was replaced, fixing the leak. I expect to have at least one of these mowers outlast me since I'm 65. I got 25 years out of Sears cheapest Tecumseh push mower and it was still running well when I sold it although blowing some blue smoke. It was used to maintain my half acre lot.
I run gas treated with Startron year round and generally never have an issue. This spring though, the Harmony started, ran, but leaked from the overflow. I found the needle valve corroded and not sealing. That part was replaced, fixing the leak. I expect to have at least one of these mowers outlast me since I'm 65. I got 25 years out of Sears cheapest Tecumseh push mower and it was still running well when I sold it although blowing some blue smoke. It was used to maintain my half acre lot.