OLD GASOLINE - The Hull Truth

tripleplay1 · 10-30-2005, 02:49 PM

Anyone have an idea what the tank life is of gasoline before the octane starts dropping off? I remember seeing other threads but dont remember what the outcome was. Does stab-bil really work to preserve? Thanks

81 CC SEAOX 23' · 10-30-2005, 05:31 PM

I dont know the exact time but there is alway octane booster. The real issue is water after a long time. How long has the fuel been sitting. Mix it into you vehicle a couple gallons at a time and get fresh fuel!

Most agree on this board that Stab-bil is a good product.

1972stamas · 10-30-2005, 05:43 PM

my project boat runs with the same tank of gas i put in 1 year ago......i did add stabil and a can of seafoam

docj · 10-30-2005, 06:28 PM

I use MDR Store & Start & have never had a problem year to year.

JupiterAK · 10-31-2005, 11:14 AM

Octane is stable for about 90 days and then begins to deteriorate. If the fuel you have or are using is or might be that old before you use it then get a good fuel stablizer like those mentioned above. 87 octane fuel stored without stablizer would be 81 or 82 octane after 6 months and about 75 octane after a year. uSE STABLIZER, then it's good for a least a year.

marker · 10-31-2005, 11:20 AM

a suzuki mechanic was telling me last week that 21-30 days ,he also said i would be better off using mid grade fuel 89,and a good stabilizer i use sea foam with good results

R_Andersen · 10-31-2005, 01:17 PM

I'm not recommending anyone do this, but just some food for thought....

I bought a used boat with twin 1989 carbed 200hp suzuki outboards. The boat had sat for over 5 years with two full tanks of fuel (125 gallons each) at the point I bought it. The fuel was stabalized when it was stored as well. I ended up draining 20 gallons from each tank and mixing in 20 gallons of fresh 93 octane. I then ran the boat on this fuel for the first few trips out with it any never had a single problem.

-Rob

HDGWJOE · 10-31-2005, 01:50 PM

When does the octane supposedly start dropping? After it goes into the consumers fuel tank or right after it is refined? If it's right after it is refined then we are probably already buying fuel approaching a month or more old. IMHO I don't pay too much attention to it. I'm worried more about water in the fuel than octane dropping off. I do use stabil just in case.

tripleplay1 · 10-31-2005, 07:25 PM

Great input...I have 275 Verados and you know the situation on having to burn 92 octane for peak performance. I will add sta-bil and try to add some fresh high octane ASAP. I tried the octane booster from the auto parts store and it went straight to the fuel filters. The gas has been in there about 90 days. I guess I forgot about the humidity and how it adds water to the fuel.

Drwhale · 10-31-2005, 08:40 PM

Check out this article......

We have seen a lot of burned pistons in the larger 2 stroke engines from gas that is not of the proper octane........Remember that the lower octane burns/detonates quicker than high octane..

The reformulated lower octane gas that we have to deal with today, in my opinion, was not meant to be used in the larger 2 stroke enngines....

www.epa.gov/OMSWWW/regs/fuels/rfg/waterphs.pdf

Pay particular attention to the last paragrah on page 3 and the first paragraph on page 4........

R_Andersen · 11-01-2005, 08:17 AM

Quote:

tripleplay1 - 10/31/2005 7:25 PM

Great input...I have 275 Verados and you know the situation on having to burn 92 octane for peak performance. I will add sta-bil and try to add some fresh high octane ASAP. I tried the octane booster from the auto parts store and it went straight to the fuel filters. The gas has been in there about 90 days. I guess I forgot about the humidity and how it adds water to the fuel.

Yoe are much better adding a few gallons of xylene to raise the octane of fuel. The over the counter octane boosters are basically worthles and may raise the octane level 0.5 at the most... Xylene has an octane rating of 117 so you can do the math to figure out your resulting octane rating depending how much fuel you have and how much xylene you add. Also, you can safely run up to 30% xylene so adding a few gallons to say 100 gallons of fuel won't hurt anything. Back in my Buick GN racing days we mixed 93 octane pmump gas and xylene to get a 100+ octane mix for track use...

Xylene can be bought at any paint store or Home Depot fairly cheaply...

-Rob