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Stuck
10th September 2013, 07:54 PM
To cut a long question short, Does it make any difference to the lifespan of fuel if it is stored in a sealed container as opposed to an unsealed one ?.
(Reading between the lines, Am I wasting my time fitting a sealable vent to my boat fuel tank in place of the constantly open breather tube which is already there ?.)

Thanks,
Anthony.

Homestar
10th September 2013, 08:00 PM
Petrol will go off after a couple of months, even sooner, but diesel can last for yonks. We used to test diesel samples from standby generator storage tanks that in some cases were 20 years old. Apart from it looking very dark and oily, if water hadn't got into it, samples sent to the lab came back fine. Usually the old tanks in the basement of multi story buildings were fine, but tanks that were close to the surface - like servo tanks, etc would get condensation into them over time which usually resulted in shorter lived fuel

bumper
10th September 2013, 09:24 PM
Petrol expands and compresses with the temperature being hot or cold if you seal your tank it will expand in the warmer weather and passably expanding your tank and warp it or it could cave it in if it turns cold after a hot day so dont seal the tank the breather is there this reason

isuzurover
10th September 2013, 09:28 PM
Breather holes on boat fuel tanks are comparatively small and usually at the end of a long hose. Therefore evaporation rates are low.

Having a breather or not won't affect storage life. As mentioned - the breather is useful to make sure the tank doesn't overpressurise in hot weather.

bee utey
10th September 2013, 10:19 PM
My ancient Honda powered mower hasn't been used for two years, I added some 1 year old petrol I had in a sealed jerry and it started on the second pull and mowed the front half of my block without stopping. So yeah, petrol may go off but not as fast as you think.

mick88
10th September 2013, 11:01 PM
I had to pull the fuel tank and the carby off one of our old mowers that hadn't been used for several years, could be almost 8-10 years! The fuel had dried up and turned into a varnish like goo and blocked up the jets etc. didn't take long to get it all cleaned up with petrol then refilled the tank with new juice and away she went!

Cheers, Mick.

Stuck
15th September 2013, 06:16 PM
Thanks for the replies but I might have shortened the question a bit too much. I mainly use 95 octane and the boat sits for up to 4 months so my question is, How long do you reckon the fuel should stay good for ?. The tank is under the floor and the boat has a cover so it doesn't cop direct sunlight.

Thanks,
Anthony.

bee utey
15th September 2013, 06:35 PM
Thanks for the replies but I might have shortened the question a bit too much. I mainly use 95 octane and the boat sits for up to 4 months so my question is, How long do you reckon the fuel should stay good for ?. The tank is under the floor and the boat has a cover so it doesn't cop direct sunlight.

Thanks,
Anthony.

Is your boat tank sealed when not in use, or is it permanently vented? Fuel hasn't got a "use-by date" as such, it all depends on the storage. Sealed cool storage fuel should last for 12 months or more. A full tank is better than a half empty one. Letting the lighter components evaporate by leaving the vent open will shorten its life. Water vapour enters permanently open fuel tanks. If in doubt fit a water trap to your fuel line.

So yeah, it depends.;) If it starts and runs it's probably OK.

gromit
16th September 2013, 11:25 AM
Petrol used to last a lot longer in storage than it does nowadays, not sure what the exact difference is.

You can get additives (StaBil) etc. to extend the storage life of petrol but 4 months shouldn't be a problem.

www.opalfuel.com.au (http://www.<b>opalfuel.com.au</b>)/assets/content/pdf/211293_BP_Opal_FS_StorageHandling_A3.pdf

www.bp.com (http://www.<b>bp.com</b>)/retail/liveassets/bp_internet/retail_new/retail_new_australia/STAGING/local_assets/downloads_pdfs/0_999/Petrol_Life_in_vehicle_tanksv4.pdf

You might have to manually cut & paste the above links.

Gold Eagle - Protecting, Preserving and Performing since 1932 (http://www.goldeagle.com.au/fuel_stabiliser.html)


Colin

Judo
16th September 2013, 11:36 AM
Petrol used to last a lot longer in storage than it does nowadays, not sure what the exact difference is.

You can get additives (StaBil) etc. to extend the storage life of petrol but 4 months shouldn't be a problem.

www.opalfuel.com.au (http://www.<b>opalfuel.com.au</b>)/assets/content/pdf/211293_BP_Opal_FS_StorageHandling_A3.pdf

www.bp.com (http://www.<b>bp.com</b>)/retail/liveassets/bp_internet/retail_new/retail_new_australia/STAGING/local_assets/downloads_pdfs/0_999/Petrol_Life_in_vehicle_tanksv4.pdf

You might have to manually cut & paste the above links.

Gold Eagle - Protecting, Preserving and Performing since 1932 (http://www.goldeagle.com.au/fuel_stabiliser.html)


Colin
When I bought my chainsaw for occasional use I was told the same thing - that petrol use to last longer, but it is different now and will go off much quicker. I was sold some small packets of stabiliser to put in the storage container so it would last for a year no problems.

blue_mini
16th September 2013, 11:46 AM
8 weeks is a general rule for how long fuel lasts, after that it clogs up jets and is generally awkward to use.

9 out of 10 failures of small engines are due to old fuel and ethanol disintegrating rubbers and seals in the carb.

mick88
28th September 2013, 06:44 AM
Maybe two stroke oil mixed with fuel prolongs it's life.
We have a little 5HP Tohatsu outboard motor that had not been started for at least 12 years, but it is always stored upright on a bracket on the shed wall. Yesterday I got it down and set it up on a stand, opened the air vent, turned on the fuel, full choke and three pulls and it was running like a clock. It is a very early model that doesn't have a rubber impeller to pump water through so no issues there either. Took it down the river and it ran perfectly.
I expected that the carby would be clogged with fuel that had turned to sludge but not in this case.

Cheers, Mick.

Tombie
28th September 2013, 10:02 AM
Old storage engines dont usually clog from old fuel, they clock when fuel hits old dried out gaskets.


My boat runs like a dog on fuel older than 3 months unless we add Stabil.

I've done this twice now - Pump tanks into drums...
Take drums to fire test area.

Tip fuel out... Stand back... Ignite :cool:

200l of old Premium goes up pretty good!!!!! :twisted: