Why does it seem that gas goes bad faster these days than 20 years ago?

Question

Years ago, I could leave gas in my lawnmower over a season and it would still start. Is it that there are no filters on the fill cans now or is it the gas spoiling because of it's changed refining?

Answer 1

Modern science has found ways to use more of the barrel of petroleum for gasoline than before.

Gasoline is in very high demand. Higher moleculear weight (MW)hydrocarbons are in lesser demand.

Refineries want to make more gasoline to fit the market need and to sell more of their raw material as gasoline. To do this they break up the higher MW hydrocarbons into smaller ones. This is called "cracking". Often a catalyst is required to achieve this and this is why the process is more often called catalytic cracking or cat cracking. The refinery equipment used is often called a cracker or a cat cracker.

At any rate, even with the cracking process, some higher MW components remain and they have too low of a vapor pressure to provide starting an engine, especially in cooler weather. Refineries pass propanes and butanes, very low MW hydrocarbons that are gases at room temperature through the fuel to achieve a level of volatility needed to start a cold engine. This does a good job of enabling the engine to start AND use up more of the hydrocarbons. The problem with this is that the low MW hydrocarbons, over time, will volatilize out of the liquid fuel - and the rate of volatilization increases with temperature which makes the residual liquid fuel insufficiently volatile to start a cold engine.

I know it is a lengthy answer but the process of refining is complex and I needed to provide a solid basis to explain this.

By the way, this process of using more of the barrel of oil for gasoline is common to ALL oil refineries, regardless of petroleum origin, refinery company, or governmental regulation. It is good business to use up more of your raw material for the existing market rather than to make material for which there is limited market.

Answer 2

They say they make it better , it means it is better for them , not us , gas also burns up faster today than it used to even when they took the lead out ...I thing now they use additives to make it not have a long shelf life , and to burn quicker so we have to buy more .....That is what that E-85 crap does, I tried that junk , it burns nearly twice as fast as high octane so you have to buy more , I do not see how that helps the environment , it helps the economy more , anyway either way you look at it they got us ....

Answer 3

Gas has many more additives now than 20 years ago. I have to keep Sta-Bill in my Motor Home and boat during the lay up periods.

Answer 4

Guess as they levels of availability decrease the saying "quality over quantity" can't be kept up :( the more demand, less product; they need to decrease the concentration and make more of it, i presume

Answer 5

UN - LEAD - ED