kinghightide Posted January 30, 2017 Share Posted January 30, 2017 I have a 75ltr underfloor fuel tank and the fuel is over 3 months old. I will need to take out the old fuel and i would like to know what is the best method of doing so without ripping out the whole floor?(if possible) Link to comment Share on other sites More sharing options...
rickmarlin62 Posted January 30, 2017 Share Posted January 30, 2017 top the fuel up with 98 oct and it should be fine...unless you need to remove tank..you don't say reason...rick Link to comment Share on other sites More sharing options...
kingfishbig Posted January 30, 2017 Share Posted January 30, 2017 (edited) If you have a click on fuel connector to your motor you can remove it from the hose, hang the hose over the transom and run it to a fuel container on the ground. Then just squeeze the fuel bulb a few times and the siphoning effect will do the rest. Edited January 30, 2017 by kingfishbig Link to comment Share on other sites More sharing options...
Franko Posted January 30, 2017 Share Posted January 30, 2017 6 hours ago, kinghightide said: I have a 75ltr underfloor fuel tank and the fuel is over 3 months old. I will need to take out the old fuel and i would like to know what is the best method of doing so without ripping out the whole floor?(if possible) Hey Matey, I often use fuel from my boat in my mower, I have a spare fuel line with a pump bulb in it . What to do is disconnect the line from your filter, connect the line about and syphen the fuel into a drum, job done Link to comment Share on other sites More sharing options...
The Incredible Hull Posted January 30, 2017 Share Posted January 30, 2017 There's no hard data of fuel going off... I think its another big myth... I've used fuel that's like 6 months old with no issues. And adding stabil to the fuel, I reckon that's another pile of baloney. How can such a tiny ratio of liquid somehow keep fuel going for another 6+ months. I would love to see some hard data and proven scientific evidence to support old fuel not to be used in engines. Link to comment Share on other sites More sharing options...
kingfishbig Posted January 30, 2017 Share Posted January 30, 2017 19 minutes ago, The Incredible Hull said: There's no hard data of fuel going off... I think its another big myth... I've used fuel that's like 6 months old with no issues. And adding stabil to the fuel, I reckon that's another pile of baloney. How can such a tiny ratio of liquid somehow keep fuel going for another 6+ months. I would love to see some hard data and proven scientific evidence to support old fuel not to be used in engines. It depends on how the fuel is stored. I think it can last a long time if it is not exposed to air or water. So it's a good idea to keep tanks full (though underfloor tanks are connected to outside air via the breather tube). I think kighhightide's fuel would probably still be OK if it's not much over 3 months old. Link to comment Share on other sites More sharing options...
Raymondo Posted January 30, 2017 Share Posted January 30, 2017 54 minutes ago, The Incredible Hull said: There's no hard data of fuel going off... I think its another big myth... I've used fuel that's like 6 months old with no issues. And adding stabil to the fuel, I reckon that's another pile of baloney. How can such a tiny ratio of liquid somehow keep fuel going for another 6+ months. I would love to see some hard data and proven scientific evidence to support old fuel not to be used in engines. Alcohol blended fuels are hygroscopic, meaning that they absorb moisture from the atmosphere, the alcohol prevents the fuel from splitting among other advantages. Typical approved shelf life is 3-4 months at 60-65 percent humidity. Non alcohol blended fuels have a longer (variable due to blends) shelf life but will eventually split forming solids known as gums. Much like mixing water and oil together, eventually they will separate. Fuel stabilizers work by forming a bond between some or all of the blend. There is many in depth, mind melting studies to support fuel degradation . Seek and you shall find. Link to comment Share on other sites More sharing options...
The Incredible Hull Posted January 30, 2017 Share Posted January 30, 2017 I just hear so much "nancy fancy jibberish" about not using fuel that's more than say 3 months old, it could destroy your engine blahblahblah and its always from someone who has heard it from someone else. Bottom line, I've used 6month+ old fuel and my engine hasn't blown up. Been doing it for years. Link to comment Share on other sites More sharing options...
The Grey One Posted January 30, 2017 Share Posted January 30, 2017 26 minutes ago, The Incredible Hull said: I just hear so much "nancy fancy jibberish" about not using fuel that's more than say 3 months old, it could destroy your engine blahblahblah and its always from someone who has heard it from someone else. Bottom line, I've used 6month+ old fuel and my engine hasn't blown up. Been doing it for years. X2 although mine is an older 99 carby outboard. Link to comment Share on other sites More sharing options...
PaddyT Posted January 30, 2017 Share Posted January 30, 2017 There is heaps of info out there- key points are this- fuel is a blend of hydrocarbons of varying volatility, the more volatile compounds will evaporate from stored fuel fairly quickly leaving the heavier longer chained molecules behind. This will reduce the octane rating of the fuel and increase the chances of "gum" forming. Turning the fuel over is a good idea for that reason. Second point is that an empty /half empty fuel tank will "breath" as it expands and contracts with variations in temperature- this will suck air from the atmosphere into the tank which holds water vapour. The water vapour will condense in the tank and sink under the fuel (water is heavier than fuel). Ethanol containing fuels will speed up this process because ethanol is hydroscopic(attracts water), ethanol also has a higher octane rating than normal fuel . Ethanol containing fuels will also potentially react with rubber/plastics differently than normal fuel and those two reasons are why they should not be used in marine/aviation activities. The other factor that lots of people dont understand is that most engines will NOT perform any better if you put higher than recommended octane rated fuel into them because the computer setups will not be set to take advantage of the higher rated fuel >the safest bet for most outboards in NSW is use 95 because as yet it does not contain ethanol (this may change in the future). Ethanol containing fuels on the other hand will not cause any problems to 99% of cars because the higher turnover of fuel doesnt let the ethanol "suck" water into the tank and the componentry of the car is designed to deal with ethanol. My tow vehicle is a Ford territory with 309000km on the clock and I have used nothing but E10 since new without a single engine/fuel related issue but my boat with a Yamaha 100 4 stroke gets the 95- again no issues after 4.5 years and 570 engine hours. Install a proper water removing fuel filter and simply use your boat and you should have minimal problems. Link to comment Share on other sites More sharing options...
Raymondo Posted January 31, 2017 Share Posted January 31, 2017 I think its the phrase "Blow up" that is the myth. An engine running poor fuel wont "Blow up" but it may damage the bore, rings, piston crowns and skirts, seals etc. Also the key word here is "May" , poor fuel isn't necessarily a death sentence for an engine but it is a little like eating sugar, tastes great but you know its doing you damage over time. The newer injected engines have finer tolerances and smaller timing parameters, putting them at higher risk of failure. In saying all that you would be amazed what a modern internal combustion engine can run on. Many moons ago when I did my apprenticeship the amount of things my fellow class mates and I poured down the carby of a running engine when the teacher wasn't looking, oh jeez here come the memories lololololol. Any who , its better to run fresh rather than stale fuel if you can. Link to comment Share on other sites More sharing options...
kinghightide Posted January 31, 2017 Author Share Posted January 31, 2017 Thanks for the informed info raiders. Much appreciated Link to comment Share on other sites More sharing options...
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