Simpler gas equipment like mowers and generators don't have enough compression to really care about anything but ancient gas, and if you run any vehicle that is multi-fuel capable it can detect and adjust compression based on a fuel's capabilities.
Ive been repairing and fixing junkers of cars, mowers, ATVs, generators, and more for 30 years and not once has bad gas stopped something from running. I only remove it if it was clearly having water raining into the tank. In every other case where I couldn't start something after sitting around for 5+ years, it was from the gas gumming up in the carb or the shitty diaphragm pump, which generally means there is little to no gas left to start with.
I wouldn't even suspect gas of ever being bad unless it was atleast a few years old. If the tank was open it could have evaporated, if the tank was closed it probably ain't great gas but I bet it would still run in anything but a high compression application.
[–] dotancohen 1 day ago
[–] JshWright 15 hours ago
[–] dotancohen 2 hours ago
The term was always called spark adjustment, never compression. Compression is the thing you worry about when milling the heads or exchanging oscillating components (rods, pistons) due to changing the physical geometry of the combustion chamber.
So yes, adjusting the spark timing does technically adjust how compressed the air/fuel mixture is at the moment of ignition. But the term used to describe it has always been "adjusting spark" or "adjusting spark timing" or "adjusting timing". Nobody ever refers to that as "adjusting compression" because the term compression is used to refer to something else.
Spark, not compression.