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Run It Dry or Stabilize It? What Manufacturers Actually Say About Storing Fuel

Updated 2026-10-29 · Written and checked by the Manual Matters team against the manufacturer documents listed under Sources.

Short answer: it depends on the brand of your engine, and the manuals genuinely disagree. Honda tells owners of its mower engines to empty the whole fuel system, tank included, if the machine will sit for more than about 90 days. Briggs & Stratton and Cub Cadet tell owners to store with a full tank of fresh fuel treated with stabilizer, and to run the engine so treated fuel reaches the carburetor. Both approaches aim at the same enemy: untreated gasoline going stale in the carburetor.

Table comparing Honda, Briggs & Stratton, Cub Cadet and Generac fuel storage instructions
Table comparing Honda, Briggs & Stratton, Cub Cadet and Generac fuel storage instructions

So the right move is to follow the manual for the engine on your machine. If you have lost it, the summary below shows what each manufacturer publishes.

What each manufacturer says

Manufacturer (document)Storage instruction
Honda (lawn mower fuel recommendations; GCV170/GCV200 owner's manual)30–90 days: fill with fresh fuel plus stabilizer, run 10 minutes, then close the fuel valve and run until it stops. More than 90 days: run the engine until the entire fuel system, including the tank, is empty.
Briggs & Stratton (How to winterize your mower)Add stabilizer per the package, store with a full tank of treated fuel, run a few minutes so treated fuel circulates. Notes fuel can begin to degrade in as little as 30 days.
Cub Cadet (snow blower off-season storage)Fill with fresh gasoline plus stabilizer, run about five minutes. Says this is better than storing empty because a dry system exposes metal to moisture and lets gaskets and O-rings dry out.
Generac (GP2500i generator manual)If stabilizer is added, run 10–15 minutes; treated fuel can be stored up to 24 months. If fuel is not treated, drain it and run until the engine stops.

Why they disagree

Honda's concern is fuel going stale in the carburetor and fuel system during long inactivity, so for storage beyond 90 days it removes the fuel entirely. Cub Cadet's concern is the opposite risk: an empty system lets moisture reach bare metal and lets gaskets and O-rings dry out. Neither is wrong; they are weighing different failure modes for different fuel systems.

Step by step: the stabilize-and-store method (Briggs, Cub Cadet, Generac)

  1. Buy fresh gasoline that meets your manual (E10 or less for every manual cited here).
  2. Add fuel stabilizer to the gas can at the ratio printed on the stabilizer bottle.
  3. Fill the machine's tank with the treated fuel, leaving the expansion space the manual specifies.
  4. Run the engine outdoors long enough for treated fuel to reach the carburetor: Cub Cadet says five minutes, Honda and Generac say 10 minutes or 10–15 minutes.
  5. Let it cool fully before covering it and storing it level in a ventilated space away from flames or pilot lights.

Step by step: the run-dry method (Honda, more than 90 days)

  1. If you have been using untreated fuel, add stabilizer and run 10 minutes first, as Honda instructs for the 30–90 day case.
  2. Run the engine until it has used all the fuel in the tank and stops.
  3. Restart if it fires, until it will not run at all.
  4. Leave the fuel valve OFF (if equipped) and store level.

Ethanol: the one point every manual agrees on

Honda says not to use gasoline with more than 10% ethanol (E10) in its mower engines, and its GCV manual calls for 86 pump octane or higher. Generac's GP2500i manual allows up to 10% ethanol and says not to use E85. No manual cited on this page approves E15 or higher for these engines.

Four-step guide to choosing run-dry or stabilize-and-store fuel storage by engine brand
Four-step guide to choosing run-dry or stabilize-and-store fuel storage by engine brand

FAQ

Should I drain the gas from my lawn mower for winter?

If it has a Honda engine and will sit more than 90 days, Honda says yes: run the whole fuel system empty. If it has a Briggs & Stratton engine, Briggs says store with a full tank of stabilized fuel instead. Check the engine brand on the shroud or label.

How long should I run the engine after adding stabilizer?

Cub Cadet says about five minutes. Honda says 10 minutes. Generac's GP2500i manual says 10 to 15 minutes. The goal in every case is to get treated fuel into the carburetor.

Can stabilizer fix old gas?

No. Honda states that fuel stabilizers will not reconstitute stale fuel. Drain it and refill with fresh gasoline.

Does the same advice apply to my snow blower and generator?

The same two schools apply. See snow blower off-season storage and Generac GP2500i storage for machine-specific steps.

Sources