Gas choice

John Mercier · 11-18-2024, 10:16 PM

The tech told you that because ethanol does not create varnish (gumming), that is the oxidation of chemicals in raw gas.

The canned gas that we sell - either four stroke or two stroke premix - is really a blend that has stabilizers in it, and is sealed against oxidation until the can is opened. Basically designed for a long shelf life.

If you ran ethanol-free and developed varnish, switching to ethanol-blend (a solvent) could cause the varnish to break free and gum up the carb. So you may need to clean the carb... which a carb cleaner mixed into the fuel should help with. It keeps the varnish that the low level of ethanol broke free in a near liquid state and works it through the system.

Once you are on an ethanol-blend, just make certain that the gas does not get old in the tank. The octane level is less of an issue, but high octane can result in overheating a motor... especially in a four stroke. That will show up as a ''bluing'' of the muffler near the exhaust port.

Pre-fire each season to determine if the gas is in need of replacement. Gas from the four stroke can be drained and added to a vehicle - the computerized fuel injection system has a greater ability to compensate than the carb system does.

So basically, we have new gasoline for the snow thrower and generator in the winter on-hand, but will fill the cars/truck with it by the end of the season if it goes unused.

11-18-2024, 10:16 PM	#1
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,460 Thanks: 3 Thanked 609 Times in 503 Posts	The tech told you that because ethanol does not create varnish (gumming), that is the oxidation of chemicals in raw gas. The canned gas that we sell - either four stroke or two stroke premix - is really a blend that has stabilizers in it, and is sealed against oxidation until the can is opened. Basically designed for a long shelf life. If you ran ethanol-free and developed varnish, switching to ethanol-blend (a solvent) could cause the varnish to break free and gum up the carb. So you may need to clean the carb... which a carb cleaner mixed into the fuel should help with. It keeps the varnish that the low level of ethanol broke free in a near liquid state and works it through the system. Once you are on an ethanol-blend, just make certain that the gas does not get old in the tank. The octane level is less of an issue, but high octane can result in overheating a motor... especially in a four stroke. That will show up as a ''bluing'' of the muffler near the exhaust port. Pre-fire each season to determine if the gas is in need of replacement. Gas from the four stroke can be drained and added to a vehicle - the computerized fuel injection system has a greater ability to compensate than the carb system does. So basically, we have new gasoline for the snow thrower and generator in the winter on-hand, but will fill the cars/truck with it by the end of the season if it goes unused.