Winterizing: Fuel in tank options?

CapnQueeg

Cadet
Joined
Jun 1, 2022
Messages
17
Winterizing my boat. It has a built in 25 gallon poly fuel tank. There is about 20 gallons of e10 in the tank, and it's been in there for a couple of months now. (straight fuel, no fuel/oil premix.)

It appears that the consensus around here is to fill the tank to the top, apply a good dose of fuel stabilizer to it, and hope for the best. That's not worked too well for me in the past, and more than once, come spring, I've wound up with a tank full of stale/smelly fuel that the outboard barfed on.

I can't get a siphon tube down the filler neck to siphon the fuel out, so I've had to remove the fuel level sending unit to get a siphon tube into the tank. That usually ruins the gasket, and I'm afraid doing this too much will wear out the threads on the retaining screw holes. (Poly tank)

What would be the downside to installing some sort of quick disconnect to the fuel line, so I can just disconnect it and connect a small electric fuel pump to pull the fuel out through the tank's downtube.

Anybody else done anything like this?
 

JimS123

Admiral
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Jul 27, 2007
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7,403
I fill my boat tanks up on the way home from an outing. Thus, my tanks are always full.

About the first of September I stabilize the tank, and then add more stabilizer every time I add more gas. Thus, upon winterizing I'm all set to go.

I have a mountain cabin with some weedwackers and lawn mowers. Most get seldom used and I often have 3-4 year old gas in them. I have NEVER seen any stale / smelly gas in those time intervals. Plus they all run, maybe not perfect, but they DO run.

I can't comment on your idea, but it seems to me that something else is going on here.

Where is the boat stored? Was your good dose, the proper dose?
 

froggy1150

Chief Petty Officer
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Nov 16, 2017
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624
I would not do qd's on a fuel line.... point of failure. But just undo fuel line coming from tank and use a inline fuel pump
 

Scott Danforth

Grumpy old guy who plays with boats
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Jul 23, 2011
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I would take the boat out, enjoy the heck out of it on the weekend and then come to the dock on fumes....
 

roscoe

Supreme Mariner
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Stabilizer should be added when the gas is fresh, not months old.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
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If your stabilized gasoline becomes smelly over the winter, your stabilizer isn't working properly. I do not have any issue with stabilized gasoline staying pretty fresh over the winter. Adding fresh gasoline in the spring is always a good idea.

At this point the debate between filling the tank and emptying the tank for winter is about the same as your typical oil debate, where everyone has an opinion, but no hard facts seem to exist.

Make sure to empty the water separator in the fall, and check it for water and rust spots, or just replace it in the spring.
 

nola mike

Rear Admiral
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Apr 22, 2009
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At this point the debate between filling the tank and emptying the tank for winter is about the same as your typical oil debate, where everyone has an opinion, but no hard facts seem to exist.
Here's a bunch of engineers from mercury talking about it, I'll take their word for it (iboats isn't displaying the link correctly, relevant stuff starts at 24 minutes)

 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
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I’ve never had problems with properly stabilized fuel; even E10…
 

tpenfield

Supreme Mariner
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Jul 18, 2011
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I have in the past used the fuel line leading to the engine as a means to pump out the fuel in the tank. Perhaps you can rig something up with a double-ended barb fitting and some clamp that give you a margin of safety than a quick-disconnect. FWIW - I usually empty the tank at the end of the season and use it for the vehicles. It is always a treat not having to buy gasoline for a few weeks.
 

Grub54891

Vice Admiral
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Jun 17, 2012
Messages
5,618
I store with however much fuel is left. This year should be 3/4 tank. No stabilizer, e-10. It always starts fine and performs well in the spring. Granted it's a 1984 mercruiser 140, but it works. On all my lawn equipment I only use preimum fuel, just because they can have issues as they sit awhile between uses.
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,737
Up here in the tundra (Minnesota) we've been using E10 for decades and if properly stabilized it is simply not an issue. Another thought in your specific instance is to stabilize and do not fill the tank or drain it. In the spring before startup top off the tank and go boating. Yes - in the early days of E10 every "mechanic" blamed E-10 for every engine issue. Many fuel system components at the time could not handle ethanol so of course ethanol was blamed for all ills. Over time all these components are now tolerant and no longer an issue. Water and dirty fuel systems are more of an issue.
 

airshot

Commander
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Jul 22, 2008
Messages
2,386
You have to use a good stabilizer, not an offbrand oddball. The Stabil and Sea Foam have been used for years with great sucess. Mix according to instructions not just pour a small amount in and forget it. Having a poly tank, corrosion is not an issue, so just add proper amount of stabilizer to the gas left in your tank, but as mentioned, it works best when fuel is less than 30 days old !!!! Also consider where you get your fuel.....fuel that becomes rancid and stinky after only 6 months is bad to start with. It should take at least a year (12 months) for fuel to get rancid, neighbor collects old cars, some of his fuel goes 18 - 24 months and still runs with fuel just starting to smell. If your fuel is bad within 6 months...try another fuel station....
 

jimmbo

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May 24, 2004
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The premise of a Full Tank, is that there is less Air going in and out of the Tank, during temp changes, dragging moisture into, the tank, where any Alcohol in the fuel absorbs it.
In the 40s and 50s fuel didn't go bad as fast, that changed when the Gasoline Robber Barons found ways to get more Gas out a Barrel of Oil by means of Catalyst Cracking, which produces a much less stable Gasoline. Add Alcohol to the Garbage coming out of the Gas Nozzle these days, and I'm surprised the Stuff doesn't go bad within 24 hours of refinement
 

harringtondav

Commander
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May 26, 2018
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2,331
I've followed @Scott Danforth 's method for the last 26 yrs. Final ride I run the tank down as far as I dare. Partially to reduce the towing load on our 110 mi trip home. I add enough Stabil for the estimated fuel left over. Winterization fogging runs it through the system. I put a kit in the Webber/Edelbrock 4 bbl after 24 yrs before selling the first boat. I found it clean as a whistle. Spring start ups and performance have been fine.
 

Drcoffee

Petty Officer 2nd Class
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Aug 26, 2021
Messages
190
I stopped using ethanol gas completely. It destroyed every 2-stroke I owned. Costco gas is pure gas and I havent had to rebuild any carbs for the past 3 years or junk my power tools. The chinese built motors and carbs have parts that get destroyed by ethanol. And whats not built in china anymore?
 

Lou C

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Nov 10, 2002
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Strange....I have 5 different 2 stroke yard tools that are running happily on 50:1 E10 gas
3 Echo machines (weed wacker, blower, hedge trimmer)
1 Husquvarna (saw)
1 Toro/Suzuki (snow blower)
the oldest is 24 years old the newest is 11 years old...
here very few (like maybe 2-3 in all of Suffolk County NY) sell E-0 gas the ones that do are very expensive, as is the canned fuel you can buy. If I were having trouble I'd use that, but I'm not for all this time.
 

JimS123

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Jul 27, 2007
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I stopped using ethanol gas completely. It destroyed every 2-stroke I owned. Costco gas is pure gas and I havent had to rebuild any carbs for the past 3 years or junk my power tools. The chinese built motors and carbs have parts that get destroyed by ethanol. And whats not built in china anymore?
I have an old classic car. Used to run leaded gas. Then it was gone and we switched to unleaded.

Back in the day we used to have to have the carbs rebuilt every 5 years or so. We switched to E10 in the early 1980's and I have not had to rebuild a carb since then. My old Ponch as been running E10 for about 40 years now. Runs like a top.

My old fishing boat has a 1970 Evinrude on the back. (That's 52 years old BTW). Every year she starts 2nd pull and other than some portable gas tank maintenance, and a few impellers, she also runs like a top.

One of the threads I recently read summarized Mercury Marine's position on E10. It described all the myths of etahnol.

It's quite clear that E10 problems are self-induced since most of us have no problems at all.
 

dingbat

Supreme Mariner
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Nov 20, 2001
Messages
14,239
Strange....I have 5 different 2 stroke yard tools that are running happily on 50:1 E10 gas
3 Echo machines (weed wacker, blower, hedge trimmer)
1 Husquvarna (saw)
1 Toro/Suzuki (snow blower)
the oldest is 24 years old the newest is 11 years old...
Have to agree… no E0 within 150 miles since 2002. Maintain 30 acres…have all the usual home and garden toys plus a few extras. Stihl, Shindiawa, Husquvarna and Honda

Only fatality to date….had to replace the fuel pump ($18) in the Cub 682 after letting it sit for 3 years with fuel in the tank.

Have more fuel related issues with the diesel tractors than all others combined
 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
10,372
I don't drain mine or run them out of gas but I start everything up every 2-3 months, make a huge racket and love the smell of 2 cycle exhaust and that keeps gas from evaporating in the carbs. The one most prone to that was the Toro because it uses a Mikuni carb with a float bowl on it not the little cube style diaphragm carbs like on most 2 strokes. On that one, I installed a shut off valve and do run it out of fuel at the end of the season. I guess they used that style carb because you don't turn a snowblower sideways and upside down lol. At least not on purpose! Anyway that 5 hp Suzuki 2 stroke is just bullet proof.
 
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