1year old gas?

[CHPerdue150hp]

Hi 150 4 2B205764
Last spring I filled up my boat with ethanol free gas which is what I use alway. I did Don’s recipe for gas treatment, and added stabile. The tank was max full and was stored because of health reasons I’m getting the boat ready for a week fishing trip to Blue Mesa in Colorado elevation 7200ft. Should dump the 26gal of fuel and replace or just burn some off and top off with fresh. I was thinking 15gal and refill would get the gas usable again?
thanks

[MichaelJ3]

Thought the marketing material on Quickstore says it stabilizes fuel for "up to a year."

All I can tell you is my own personal experience:
Given the winters here in MN, I routinely have stored my PWC's from about Mid Sep to Mid May every year for the last ten years, with zero fuel related problems, not even a carb rebuild in 10 years...Always run BP ethanol free, always stored full, always treated with Marine Formula (Now 360) Stabil at the bottle recommended dose for storage.
The past 2 winters, I have stored my boat with a full tank of the same fuel (BP ethanol free), and the correct doses of QuickCare, QuickStore, and QuickKleen from Early November to Mid/Late April...with no fuel related issues. Fired up on first crank in the spring, and burned all 34 of the gallons in the tank, with zero performance issues.

So...I can attest that I have done 6-7 months...in mostly cold weather. This, generally, is the recommended winterization/storage procedure boat dealers recommend up here in the northland...the theory is minimize the amount of air in the tank to minimize condensation in the tank through the temperature changes.

All three machines get professional wintizeration by qualified mechanics following the recomended procedures by their respective manufactures (which on the PWC's includes draining the carbs)...yes, I could do myself, but if I have it done and a block cracks from freezing...and I had the job done by the shop, the shop is on the hook to get me back whole again...plus its a good time to have the stuff inspected by people skilled in their trade...

I'm and waiting for Don's answer though...it would definitely be SAFER to put fresh fuel in.
To me, the strategy of "freshening up" with half the tank, doesn't seem to be a big benefit...I'd either dump it all, put in fresh, and run it a little before your trip to get the old stuff all the way through it and ensure its good, or take my chances...The 15 month thing feels kind of long to me....

[R2Tracker]

I would empty the entire tank and start with fresh, I would not risk spoiling a week long fishing trip. I am crazy/cheap enough however, that each time I stopped at the gas station to refuel my vehicle, I might leave room to add a few gallons of the old stuff, just to burn it up, of course assuming it passes a visual and sniff test. How else does one properly dispose of that much old fuel?

[EuropeanAM]

Big difference between "up to a year" and "you'll be fine at 7200ft Elevation after a year". BIG Difference.

I would strongly suggest siphoning that fuel out, and running it in your vehicle. Start with a FRESH load of fuel in the boat, and of course, check to make sure you're up to date on all of your Annual Maintenance before heading out.

[CHPerdue150hp]

Ok, thanks every one there is new oil change with new filter in the engine, Im still less than 100 hr. On it. I siphoned the gas out, and will be heading over to the ethanol free pumps and doing a fill up with the usual treatments, Don’s recipe of Quick Silver 1&2 and 360 stabil at the recommended use. I don’t want to damage any thing in the engine.
Thanks to all again.
CH

[SilverFox579]

Forget Stabil if you're using Quickstor they do the same thing. Quickare and Quickleen for regular use 30 days or less (see the fuel topic in the FAQ), if extending beyond 30days, Quickstor is recommended. Quoted from the fuel FAQ at top of forum:

Fuel Additive Recommendations:
-Stabilize fuel ANYTIME fuel will not be consumed and replaced within 15 days!!!
-Verado Models: Quickleen in EVERY TANK OF FUEL. You CAN combine Mercury QuickCare or QuickStor Fuel System Treatment & Stabilizer with Quickleen. Use the recommended "dose" of each product per the bottle instructions.
-Quickleen may be used in ANY Mercury engine- it helps to prevent/remove carbon buildup (primary purpose).

------------------------------------------------------------------------------------------
"Mercury Component Cocktail"- for EVERY tank of fuel, whether or not your fuel contains Ethanol: (Chemically, this works much the same as the previously recommended (and now to avoid alcohol content) cocktail, and requires less components.) This is Don's Preferred "Cocktail":

-1oz Mercury QuickCare per 5 gallons fuel
-1oz Mercury QuickLeen per 5 gallons fuel
(If leaving fuel in boat for more than 30 days, be sure to also add Mercury QuickStor).

[CHPerdue150hp]

I have not been using quickstor, I can’t get it here locally. So been using regular Staybil, up to 2yr for fuel. I don’t use any gas with ethanol. So don’t figure I need to use an ethanol treatment. Just a cleaner, and storage treatment. The 1 1/2 year old gas i drained smelled like gas and the color looked ok, how ever I emptied the tank and put fresh in the tank with staybil and Don’s recomended quickcleen. This should be ok for at least a year.
CH

[potomacbassin]

I have not been using quickstor, I can’t get it here locally. So been using regular Staybil, up to 2yr for fuel. I don’t use any gas with ethanol. So don’t figure I need to use an ethanol treatment. Just a cleaner, and storage treatment. The 1 1/2 year old gas i drained smelled like gas and the color looked ok, how ever I emptied the tank and put fresh in the tank with staybil and Don’s recomended quickcleen. This should be ok for at least a year.
CH

Just out of curiosity, why do you use Stabil if you say you don't need an ethanol treatment?

[SilverFox579]

Simple, to stabilize the fuel to help prevent oxidation and octane degradation, which occurs whether or not the fuel contains ethanol.

[Dubee]

Simple, to stabilize the fuel to help prevent oxidation and octane degradation, which occurs whether or not the fuel contains ethanol.

How does stabil help with that?

[EuropeanAM]

It stabilizes the fuel.

[potomacbassin]

It stabilizes the fuel.

So it's not just a 'catchy' name

[EuropeanAM]