Leaving as in the tank, how long?

[BenKeith]

Got a question on how long ya'll think gas will hold it's octane.

Normally I only buy enough gas for I plan to burn. The last time I ran the motor, about two weeks ago, I had only ran a short time when it melted #1 piston, (dumb mechanics fault and I ain't saying who that was), and it's going to be another week before it's run again. Tank is usually almost emty when I load the boat but this time it's almost full. ABout 38 gallons of gas.

Motor is a 200 looper with about 145# compression, WOT is 7K

Boat has sit in the driveways Georgia noonday sun (low 90's temps) all this time. Tank is covered but it still gets pretty warm.

After three weeks, would you dump it, not worry about it, just not run WOT until that tanks gone, dump half and refresh the rest with a fresh fill up?

[BarryStrawn]

Three weeks? - I wouldn't worry about it.

[Raceman]

When my retired buddy made one of his annual treks to Wisconsin when he still worked for Merc, he said there was an oil company engineer there doing some kind of seminar. He said that today's gas starts major deterioration in 6 mos.

I'd think enviormental conditions would make it shorter, but surely several mos. would be safe.

[BenKeith]

I know three weeks ain't much for the gas. My concern was the octane. I know a lot of this junk we buy out of the tanks now days will barely run a motor and you're hoping you get 93 octane out of the pump. (the last test I saw showed 93 actually being closer to a real 83 but that's beside the point) I also know it don't take long for high temps to drop the octane of gas fairly quickly. Since the boat is not shelterd, I was just wondering how quicly and how some of you REAL hotrodders felt about it. Most of ya'll have played with these things a little more than us wannabe's.

Thanks for the input.