Reply With QuoteHow long has it been in there???
hi guy's just wondering if it is true that premium fuel go's bad after a while ??? ya c last attempt to get the alibi out i put 400lts fuel in a prob only used 5 ltrs ( engine prob's at ramp) that is sorted now....
need to know what everyone thinks about this........WILL IT BE OK STILL OR NOT???????
How long has it been in there???
All modern fuel goes bad. Leaded fuel was a lot more resistant to going stale .
Premium is no more protected than unleaded. Moisture, humidity , temperature oxidation from air accelerate the process over time so how long is a key question. Fuel companies were saying that there is a fair bit of degredation after a month and significant at 3 months - they don't really say what damage it could cause or how to test it.. Depends if it came from a high turnover bowser and was fresh to start with and if fuel in your tank already was fresh. You can't refresh stale fuel all you can do is dillute it and the whole batch will degrade faster if not all used. Water in fuel and other contaminants can lead to gelling, acid deposits in teh bottom of tank.
With tanks I assume quite full it may be a better scenario as you have less air in the tank and a good filter system will get sediment and water or any gelling.
If motors are heavily loaded , overloaded boat or overpropepd and at their limits than you have more chance of engine damage especially in 2 stroke motors. Labouring a motor just on plane etc is no good nor is WOT. The light volatiles ( bits that go bang) evaporate off and leave a lesser power fuel that needs more for the same bang and then burns hotter. This can lead to piston tops havig holes in bad cases of old fuel and overloded motors. Lubrication oil may not mix as well . 4 stokes are not as susceptable a oil is seperate and helps cool a over loaded motor and bearings , bore , underside of piston all stay lubricated. Valves and seats can have issues.
Injected motors and ones with computers and exhaust gas sensors add more fuel to compensate for less bang in the fuel as they expect certain revs at certain fuel input and if present for certain settings in exhaust temp etc.- Stale fuel doesn't burn as well and you end up with carbon deposits in exhaust and so on.
Not a exact answer as not enough detail in the question.
If you had a motor issue again I would have dumped a batch of stabil style fuel stabiliser in the tank on the way home and that would give you a couple of months leeway.
alibi
i have read lots about this subject and all points towards fuel going off pretty quickly, but in my personal experience owning a big boat with big fuel tank (520L) i have not had any adverse fuel issues with leaving 200 - 300L onboard for up to 3 months.
a typical trip for me will have 200-300L of old fuel leftover from the last trip (premium). it may have been sitting for up to 3 months. then i top up with 200L or so on the way to the ramp and have never had an issue. motor is a yam F250.
steve
yer thanks guys its a 225 supercharged verado, the motor , the tank is 250 ltrs x 2 and they both been full for about 3 months, iv never had any probs before but they were half full and i added 100 ltsw though...
about 3 monthsOriginally Posted by lethal098
Mate 3 months is nothing it'd be fine, I had fuel sitting in my Honda eu20 generator for about a year and a half and it still ran perfectly when I went to start it. I also had fuel in my 2011 ABS CBR1000 which I didn't ride over winter and it fired and ran great.
Prior to the 1770 M&G, I was in the US for three months & the boat was last used some six weeks prior to that. I topped up a 300L fuel tank containing standard ULP with about 175L of the very expensive 97 octane & the 175 Zuke engine never missed a beat during the M&G. I am sure that petrol does lose volatility over time but there appear to be a lot variables which affect this. Hot weather will cause my tank to fume off where as in winter there is no petrol odour. Three months should not be an issue.
ROLL TIDE, ROLL.................
Regards,
Peter
Your generator is not running at 6000rpm or pushing a heavy object through a medium of great friction.
The best recommendation is to go by the engine manufacturers advice. Around 8 weeks is considered the lifespan of petrol before it is considerably degraded. This degradation increases in warmer climates (Qld as opposed to Melb).
Fuel that is going to be left in a tank for a period of time should be treated with a fuel stabiliser to keep it fresh. Topping up old fuel with new will not make the old fuel any better. The whole load becomes tainted then.
Whenever the fuel debate is raised there is always opposition to discarding old fuel and always people popping up who have run their outboards regularly on super old fuel.
Sure, your outboard will probably run on the old fuel and certain models are more susceptible to old fuel than others but you cannot see the internal damage it is causing.
At the end of the day there is commonly a mental block about discarding stale fuel. Although, I think $50 worth of fuel dumped out is safer than the cost of a rebuild.
Any vessel with non removable tanks that are likely to have fuel left over, should be treating their fuel. Theres no excuse and its poor fuel management practices to have such situations occur. Engines get destroyed by stale fuel constantly!! Just pop into any mechanics shop and ask them. It's not an isolated event.
Cheers
I have a full tank at the moment 200ltrs ready to go. But when I filled it 6 weeks ago I used that Quicksilver fuel stabiliser. I will definatly use it from now on use every time I fill it.
Why do I hear so much about stale fuel and potential problems from boaties ?
Light Aircraft run on Avgas, slightly higher in octane rating than petrol (100) and have comparable volumes of fuel left in tanks for months at a time. (typical light aircraft will hold 200-300l when full) The potential conseqeunces of any aircraft engine stopping unexpectedly are far greater than a boat motor stopping but I never hear of pilots worried about the fuel ? Perhaps the small lead content that is still in Avgas plus antioxidants that helps keep it fresher ?
From the Shell website:
Avgas 100LL has lean mixture octane rating of better than 100 whilst its rich mixture octane rating
exceeds 130. The combustion performance is equivalent to Avgas 100/130. Avgas 100 LL
with lead content of less than 0.56 gm/ litre is suitable for aircraft engines certified to run on Avgas 80/87.
Shell Avgas 100LL contains an antioxidant giving good oxidation stability and
protection against formation of gums and residues in fuel system components.
I just answered my own question. Which leads now leads me to ask, if petrol companies can make a fuel for aircraft that is stable over time, why dont they do they same for the boating market ?
Price is the answer , demand and the fact that additives ar easier ways to control gum and contamnants for short periods of time the average car user needs to use up fuel. Car motors are not usually under the same constant load and the fuel standards ( I use that term loosley) for cars is so wide you can drive a tanker full of paint thinner through it.
Avgas is pure and consisant ad still has lead in it,tght standard and quality, no gum, no additives , tanks/ pumps are all checked and monitored. Don't know what the current stuff does but stored correcty the mil spec avgas used to good for 4-5 years with constant checking. Then again you expose avgas to oil, any contaminants or worse still sunlight or artificial light and it degrades like normal fuel.
Someone who flys now shoud know more
Some marinas used to buy boat fuel which has additive package and no ethanol but not sure who these days or if any. Was similar to remote area drum fuel that also lasts well and being in sealed drums helps obviously.
I've run motors on avgas , correctly jetted and set up and it is a pleasure to pull the down and see how clean they are and how filters are clean. Using avgas in anything but a plane now due to the lead is not possible and with security you can just pop out to the airport bowser and ill up a drum at city airports. They were going to remove the lead years ago ad last I heard that it was going in 2017 if they can find a replacement.
My father is a pilot he use to own a piper senca 2 turbo prop VH-HWU and he told me avgas at the time of owning his plane was cheaper than regular unleaded. Not sure on current pricing but you could only buy avgas if you held an account with the fuel supplier.
What is the expected useful life span on unleaded when using fuel conditioner?
What is the prefered brand? or are they all pretty much the same?
They say up to 12 months with stabil. I asked years ago and couldn't get a recomendation from one fuel company and got a lame answer of just use fresh fuel or buy their high spec drum fuel when they do a batch of it. Once the drum is open all bets were off.
Be good if someone could email the fuel companies and get a straight answer as you would assume the brand of stabiliser in the shop at their servos should be compatable???? with the fuel out of the bowser. I am not sure if a fuel company actually sells a specific stabiliser for their fuels.
I find the prices of it a bit rich and not sure what alternatives are out there with other brands.
Some stabilisers work in diferent ways be it holding stuff in solution or forming a tension on the top layer of fuel in the tank. Some don't cope with fuel that gets disturbed or large temp ranges whilst in storage.
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