Fuel preservation
 

Question to those who winterize their boats and the fuel you use .............how do you keep it fresh over the long winter before boating season starts up again?
I'm aware of fuel additives such as GAS-SHOK and others to stabilize & stop Ethanol/gas fuel problems over a long winter layup, but how long can you prevent
water condensation in fuel tanks before harm can occur?.......last season I switched from regular pump gas (Shell V-power) to AV 100 LL fuel mainly for the longevity
of it's fuel staying fresh and octane, but I found that my engines where running lean (EFI's 575's) which could cause my exhaust valve to burn.....What fuel do you guys
use and how do you keep it moderately fresh between boating seasons?............Anybody using 10 to 15% AV fuel with their regular gas fill ups?........Thanks, Scippy

Ayuh,..... I use nothin' but ethanol free gasoline, 'n add Sta-bil to the last tank of the season,.....

I use marine stal-bil in every tank of ethanol pump gas. 1oz per 10 gallons than 2oz per 10 gallons for the entire tank when wintering. Also put in Startron additive when winterizing. Also do the oil soup mix in separate tank to run thru engine when winterizing. I winterize with a full tank of fuel. Never had a fuel related problem in 7 years of ownership on current boat. I still have some gas from last year in my tank, (because lack of use). I have added fuel this year but still have a few gallons of last year's fuel in tank. Engine never skips a beat.

Star-Tron blue fuel treatment EVERY fill up.
Double up with StaBil treatment for winter lay up.

Never trust that the fuel you get is actually ethanol free. I found that out the hard way.

Non-E gas and nothing else in boats
I use sta-bil in anything that sits with E-10

Short story.......My 35 Cig was restored in '96 used less than 10 hrs' then put in storage ~ fuel was never drained until I purchased it in '16 ~ used USA fuel service to drain a 1/2 tank of varnish then clean tank add new sender, fuel filters etc; etc;
a mechanic with Flagship Marine Engine Co. recommended AV fuel ~ filled up @ Punta Gorda airport ~ the engines (EFI 575'S) fired up for first time in 20 years exhaust smelled wonderful! ~ been using AV fuel ever since. ~ my concern is
O2 sensor notes engines running lean which can cause exhaust valve erosion ~ I've read where AV fuel can cause VSR (valve seat regression) in some plane engines ~ the fix was to change out valve's to hardened steel ~ my question is ~ My
plan is to introduce my engines to regular pump gas as the AV fuel burns away ~ is there any problem by mixing AV gas with pump gas?............I have Arizona Speed & Marine EFI'S (old skool stuff) atop the 575's tall boys.

i just run it low, or fill it up. add stabil and then either fill up with fresh or cruise it all the way until it has more fresh and i can run hard.

I drain the tank, then add 10 gals of Av gas + 1 qt 2-stroke oil + Stabil all mixed up in 5 gal cans then poured into boat tank. Remove fuel filters, dump and re-install. Run engs until the 2-stroke smoke appears, then stall eng with oil fogging spray just as the 5 gal canister (connected to muffs) of pink anti-freeze goes dry. Winterized...

I have always ran my tanks empty or very low after treating the fuel for the past 20yrs with 280/300x/300xs outboards. Just didn't like starting new season with old fuel and engines required premium. Now I'm running I/O's just treating and running low for last run.