Storing gasoline without stabilizer.

Modern gasoline, especially ethanol-blended fuel, begins to degrade within 30 days under normal storage conditions. By three to six months, untreated gas has oxidized enough to form gummy deposits and varnish. By a year, it can clog the fine passages in a carburetor to the point where the engine won't start, or runs roughly and dies under load.

The problem is that you won't know the fuel has gone bad until you try to start the generator. Which happens at the beginning of the outage. Which is the worst possible moment to discover the carburetor is varnished.

What actually happens to old gasoline.

Gasoline is a mixture of hydrocarbon compounds. When exposed to oxygen, some of those compounds oxidize and polymerize, forming thick, lacquer-like deposits. Ethanol in the fuel attracts water from the air, which separates from the gasoline and sits at the bottom of the tank. That water layer corrodes metal fuel system components and feeds bacteria that can further clog filters and injectors.

The carburetor's main jet is a small precision orifice, typically about 0.030 to 0.040 inches in diameter. A layer of varnish thinner than a human hair can partially block it. The engine starts with difficulty, runs lean under load, and dies. Cleaning a varnished carburetor requires disassembly, a carburetor cleaner soak, and sometimes professional service — $80 to $200 at a small engine shop.

The $15 fix.

Fuel stabilizer (Sta-Bil, PRI-G, or similar products) works by slowing oxidation and displacing water. Added to fresh fuel at the correct ratio, most stabilizers extend shelf life to one to two years. Some formulations claim longer.

The protocol is simple: add stabilizer to the gas can when you fill it, not after the fuel has been sitting for months. Stabilizer added to degraded fuel slows further degradation but cannot reverse existing varnish formation.

One 8-ounce bottle of Sta-Bil costs about $10 and treats up to 20 gallons. One bottle per fill. Cap the can tightly after adding stabilizer. Store in a cool, ventilated location away from heat sources and living spaces. Mark the fill date on the can.

The rotation discipline.

Stabilizer buys time. It doesn't eliminate the need to rotate fuel. A good rotation schedule: treat and store fuel in fall before hurricane season and winter storm season. Use stored fuel in spring and summer through lawn equipment. Refill and re-treat in fall. Nothing in the cans ever sits more than a year.

Run the generator itself on fresh fuel at least once a year. Start it, run it under load for 30 minutes, check the oil. This confirms the unit works, burns any residual stale fuel from the fuel system, and gives you a chance to address maintenance issues before you need the machine for real.

The propane alternative.

Propane doesn't go stale. If gasoline management is a discipline you won't maintain, dual-fuel generators that run on propane are a direct solution. A 20-pound propane tank stores indefinitely and can be cycled through normal grill use. Propane burns cleaner, produces less carbon monoxide per BTU, and requires no carburetor cleaning.

The tradeoff: propane has about 73% the energy density of gasoline by volume, so runtime per dollar is slightly lower. For most households, the reliability advantage outweighs the efficiency cost.