It's "best" to use gas within 6 months...it doesn't "go bad".
Most issues with "bad" gas are related to small carbureted engines. A little fuel gets left in the carb and when it evaporates off, it leaves behind gummy residue that blocks of the tiny passages in the carb. Bigger engines are less prone to this as they don't have such tiny passages in the first place and because fuel injected engines don't mix fuel and air until it's in the cylinder, there is less of an issue with evaporation while in the fuel delivery systems.
How I would handle it depends how much gas is in the tank, how easy it is to syphon out and what kind of trips you have planned.
- If it's mostly empty, just fill up and it will dilute the old gas.
- If you have a trip long enough to burn thru a couple of tanks, topping up and burning it off makes a lot of sense.
- If you don't have any long trips, topping up and burning it off before filling it back up is an expensive option. (80gal at $4/gal is $320...plus your time driving along with wear and tear on the MH for no purpose other than burning off the gas)
- If it's not hard to syphon out and you aren't planning any trips long enough to burn off a couple tanks of gas, you could syphon out 4-5 gal and mix into the car gas tank when it's 3/4 full. Repeat and eventually, that will leave it empty enough that when you do fill up, the old gas is well diluted with fresh.
In the future, plan to add fuel stabilizer before putting her into storage but even then I prefer to dilute when pulling out of storage.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV