Let's finally decide on the stale fuel debate......

[mcgyver]

I have spent hours on this...and I'm not sure if I'm any closer to a definitive conclusion. I have 40 gallons left in my onboard tank, run it through a Raycor filter before it hits my Yamaha 150 (2 stroke oil injected). I've stabilized with Stabil but not until just recently (2.5 months after last fill). I've read about the volitiles offgassing from the fuel leaving the gum and varnish. Questioned fuel that is stored by the big companies for years. Read about condensation if tank not kept full (85 gallon aluminum tank). I live in the Pacific Northwest so condensation is an issue. 40 gallons is a little too much to run through my Avalanche and to be frank am i flirting with the same problem I "might" have with my Yamaha? Is there a clear cut answer?

 

[sigma]

Re: Let's finally decide on the stale fuel debate......

Here is the answer

Stabil works good, fill your tank and stabil it. Also run some through the engine before storing so the carbs get it as well.

Want even better? Get some PRI-G and use that. It will stabilize fuel and IT WILL BRING BACK OLD GAS to new.

I have used and tested PRI-G in old gas an it works period.

I have stored boats for 6 month and even longer. I have stored boats at 40 below zero and no problems

 

[robert graham]

Re: Let's finally decide on the stale fuel debate......

Plenty of opinions on this. 10 weeks is quite a while sitting with no stabilizer, probably the very least that I would do is fill the tank up with fresh fuel (40 more gallons), ad a double dose of Seafoam or Stabil Marine, keep an eye on your Racor filter, run it and hope for the best. Another variable factor is if the fuel laying in your tank was 10% ethanol or straight gasoline. Good Luck!

 

[Knightgang]

Re: Let's finally decide on the stale fuel debate......

2.5 months is not a long time for fuel. When I was in Iraq, my boat sat for a year with no stabil in the fuel with about a 1/2 tank (36 gallon tank). Because I did not run stabil and get some into the carbs, I did ave to pull hte carbs apart and clean them, but when I did, I filled the remaining 1/2 of the tank with fresh fuel to mix it up and had no problems. If you have already added stabil, I would finish filling yours with fresh fuel, run it to get it into the carbs and then do your normal winterization... you will be fine...

 

[robert graham]

Re: Let's finally decide on the stale fuel debate......

Opinions galore! Another variable is how long the fuel sat in the tanks at the depot and then sat in the tanks at the gas station. If fuel is degraded badly you can risk plugged carbs/injectors giving lean condition and worst case a fried piston. No perfect definitive answer here. The Racor is probably your best friend on this. Good Luck!

 

[Silvertip]

Re: Let's finally decide on the stale fuel debate......

Fuel does not go sour in under 90 days. While it certainly begins the process of degradation the day it leaves the refinery, it will no cause problems in 90 days (condensation issues excepted). Treat the fuel, add some fresh won't hurt and then as suggested, run the engine to get the treated fuel into the fuel system. Put the boat to bed. Here in the tundra we store our boats for six months and treated fuel is not an issue. I do question the statement about "bringing stale fuel back to new".

 

[robert graham]

Re: Let's finally decide on the stale fuel debate......

Assuming the fuel in the tank may be questionable, maybe run your motor off a seperate tank of strongly treated/stabilized fuel to be sure motor is stored with "good" fuel in it over the winter. Just an idea! Good Luck!

 

[zzzzz]

Re: Let's finally decide on the stale fuel debate......

NOTHING...repeat - NOTHING ! makes old fuel new

 

[likalar]

Re: Let's finally decide on the stale fuel debate......

Here's another opinion, maybe overkill: I've had Honda, Evinrude, Tohatsu, and now Yamaha outboards. If storage is planned, I fill the tank and treat the gas with Sta-bil or similar. Run water thru the muffs, and run/flush the engine to get the treated fuel into it. Then I disconnect the fuel line at the engine, and run it 'till the engine starves of fuel. Then I pull the plugs, spray fogging oil, button it all up. With small engines (Stihl, Honda) chain saws, snow blower, etc, I do pretty much the same. The good thing about this is that the float bowls, carb jets, etc. are now mostly dry, and any fuel remaining is treated, and gumming of gas in these parts is less likely. 33 years of doing all this, and every engine starts quickly months later (Except the chain saw. That one hates to start). Good luck.
P.S. The fuel in the flexi line and bulb from the tank should be drained back into the tank.
Larry

Update: I just re-read the original ??? above. Sorry, I didn't answer any of it, did I? Senior moment, once again. ;-)

 

[reeldutch]

Re: Let's finally decide on the stale fuel debate......

opinions about fuel differ because there is different types of fuel out there.

if you are pumping gas witch contains 10 % Ethanol bet your fuel has a shelf life.
from the time that the fuel gets mixed with Ethanol it has a shelf life for 3 months.

so if you pumped say 30 gallons in your tank in august burned 10 gallons and topped it of in december with 15 more gallons so you have 35 gallons of fuel, your fuel is as good as it was pumped in august.

its very simple you dont drink milk let it sit for a week and ad fresh milk to the old milk and think its fresh again. Daah

so why is it for people so difficult to accept that fuel with Ethanol has a 3 month shelf life.

after every fill up you should add stabilizer to extend the shelf life from 3 months to 6 months.

if the gas is not stabilized forget about the spring you surely run into trouble with water in your gas.


what we do in our Marina is advise people who are using 10% ethanol to run the tank as empty as they can.
stabilize the 5 or 10 gallons that are left in there and take a fuel sample out of the tank and leave it out in a glass snapple botle over the winter and before starting up the engine in the spring take a good look at the fuel sample.
if it has fase seperation pump out the 5 or 10 gallons of fuel in stead of 30 or 40 gallons.
they charge 6 dollars per gallon to get rid of bad fuel so say you are so lucky to have 40 gallons in the tank and it went bad because you still had gas in there from august that you didnt stabilize bud you stabilized the 15 gallons that you topped the tank of with, here is your bill.

40 gallons X $6 240 dollars
if you got it in your vst tank you have it in your fuel rail clean that all out takes you about 2 hrs in the shop. 200 plus some parts (filters) may be a gasket)
if your lucky your bill will be 500 dollars

so thats what i would do

does it get condensation in there with a empty tank yes it does but it will on 5 gallons be almost nothing that my yamaha water fuel seperator cant handle.

it works for me never have a problem winterize about 80 boats per season.

 

[rodbolt]

Re: Let's finally decide on the stale fuel debate......

I am with reelducth only we winterize about 4 times the boats he does.
most hulls manufactured prior to 2009 and some 2009 models have fuel tanks vented to the atmosphere, means that ethanol can suck moisure,water, through the vents especially here in our high humidity area.
for blended fuels we reccomend running the tank as low as possible,run fuel stabilizer at every fill and leave the tank as empty as possible for storage.
I have seen blended fuels even with stabilizer go bad inside of that 90 day window.

 

[robert graham]

Re: Let's finally decide on the stale fuel debate......

Hey guys, I came upon this site called: Marine Fuel Additives Safety Data Sheets that's got a lot of information on the formulas, pros, cons, etc. on this subject. The part that gets me is that there's so many different types of alcohols and naphthas. Check it out. Think I'll stick with the Stabil Marine until a better product comes along. Good Luck!

 

[scoutabout]

Re: Let's finally decide on the stale fuel debate......

...disconnect the fuel line at the engine, and run it 'till the engine starves of fuel. Then I pull the plugs, spray fogging oil, button it all up. With small engines (Stihl, Honda) chain saws, snow blower, etc, I do pretty much the same. The good thing about this is that the float bowls, carb jets, etc. are now mostly dry...

I do pretty much this with a couple of variations. This year I added a fuel valve south of my water seperator for ease of running the motor dry....

But once dry, I drain the carb bowls via the screws on each bowl. I noted with interest that only the top carb bowl was really dry. Each of the remaining three carbs down the engine were progressively more full of fuel with the bottom carb bowl being about full.

Then I fog through the port screws on the side of the motor with a flexible tube. Then I crank the motor with no fire a few revolutions and replace the screws.

 

[hobohro]

Re: Let's finally decide on the stale fuel debate......

Interesting Site: http://www.fuel-testers.com/index.html

 

[ENSIGN]

Re: Let's finally decide on the stale fuel debate......

NOTHING...repeat - NOTHING ! makes old fuel new

The best reply I have read.

 

[john3931]

Re: Let's finally decide on the stale fuel debate......

One thing that I have found out on the whole fuel situation, there is positively, absolutely no rhyme or reason. I have seen gas go bad in a month. I have had people get bad gas out of the pump. The lucky ones never have any problem. The is no relation to brand of gas or station that it comes from. Doesn't matter is the ethanol is blend at factory or the pump. The gas now adays just sucks. No matter what you do, there is still a chance that you will have problems.
In the old days, I would dump gas in a jar and the water would settle to bottom and gas on top. I have had a couple instances where I dump fuel in jar, the water was on the bottom gas in the middle and something else on top.

 

[King P.V.]

Re: Let's finally decide on the stale fuel debate......

Here's a suggestion. Go buy ...say, 25 gallons of fuel. Leave it on the back porch in an open container, protect it from direct rain water intrusion. Watch all those vapors raise away and float off into the sunset, every day. Six months from now, pour the remaniing "fuel" (or what's left of it) into your nice car or pick-up... See any problem with this senario???
Take this same container of fuel and before you leave it on the porch, add the correct amount of stabil, then do the same... Any more or less concerns??

Here's my answer. Nuthing you can do will prevent the escaping of the "good thing's" in your fuel to the atmosphere. Stabil will prevent the formation of gum and varnish in the tank, fuel lines or carb but will not stop the loss of the perfumes and aromatics design'd/built into the fuel. These chemicals are what makes you engine run to the degree you expect it to. Right??? Now, here's the clincher. Topping off you tanks in the late fall , (with "winter blended" fuels) will not allow you to add any fuel, 1st time out on the 1st hot/warm day in the spring. Then you'll be complaining how your boat runs so s*$##y, has no power, idles crappy, etc.... It has 6 month old fuel, no varnish or gum build-up possibly, but it's still 6 months old..........sure it runs crappy. Heck, I'd expect it to. Don't top off your tanks. That way you can add at least SOME fuel in the spring prior to the new boating season. Oh, and always treat your gas with fuel stabilizor!