Whether having a full tank or part filled one and the air space above is not so much of a consideration as the water already in the ethanol when you put the petrol in the tank. More fuel in the tank means more ethanol and more water which is not going away during winter storage. All that water would rust the tank . In my opinion if the van is laid up for the winter I would drain off the remaining fuel and leave the tank dry. The fuel would separate and go off anyway during storage and best to start off with new fuel in the Spring.
Or for the last fill before winter fill it with E5 super unleaded & pop some additive in also as an extra measure to counteract any ethanol.
I have to admit I'm tending to go mostly empty for storage, but not completely empty! I would be concerned that could cause problems with dirt in the tank getting into places it should not. The existing advice, as Mike says , is to leave full but does this need to be updated due to E10? Edit:- @Gooders, good idea about full tank with minimal ethanol if possible
Of course the other downfall of brimming the tank is that if the fuel did go off that's potentially £80 down the drain (metaphorically speaking). This is worth a watch...
Van usually goes away by the end of October & back out early spring time so probably about 5 months. I’ve never noticed any issue with aging of the fuel over that time.
I've read some academic research papers, was involved in some engine dyno tests on E10 fuel in classic cars and learnt to use the Ricardo WAVE engine simulation package. Result? I decided to ignore the whole E10 thing. I just don't know enough to optimise all the engines I have. I accept that the modern stuff with sensors everywhere and closed loop control can cope with whatever I put in so I'm optimistic and put Super/E5/98 octane in the high performance car and put E10/Regular in the runabout. The classics ran on absolute junk back in the day so E10 is far better than they were designed for and it doesn't go off to the extent that some would have you believe. If you've found a good set up with the fuel that you can easily get, then I suggest that you stick with it. If you've got problems, then it's more likely to lie in your ignition and carb set up than the petrol itself. As an aside, I had a Bedford CA icecream van for a couple of weeks one summer as a student job. Rather than spend money and fill it up with fuel at the end of the stint, I dropped in at home and chucked in a few pints of a mix of paraffin, methanol, castor oil and nitromethane; it ran fine
That brings back memories! I worked at Ricardo for many years, and spent far too much time with WAVE, using it to predict intake and exhaust noise and how they change with tweaks to resonators and muffler designs. Worked remarkably well, for a one-dimensional simulation with pretty large elements.
Technically, water will not cause any rusting unless air is also present. You could fill your tank with deaerated water, seal it and it wouldn't rust. As long as there's no air in the petrol, a full tank would be safer than a half full one.
Keep your two stroke mix in properly airtight containers (like the polypropylene spare fuel tanks). Then it doesnt matter so much as not much gets out and no water gets in. Then you can use E10. Dont leave fuel in the power tools as they dont have well sealed fuel tanks, pour the spare fuel back into the airtight container. My small outboard motor keeps fuel for months OK because it has a screw down air vent that makes it pretty airtight.
Yeah but then I have to store the unused fuel in a canister which may go off, well mower wise but of course the saw is getting regular use so not so worried about that.Ah, Mike has answered the problem as you have. Cheers fellas
On a hot day once that container is half full, I bet its lid leaks otherwise it would burst..not good for long term storage, I would transfer it to a better can, or it will go off.. the good polypropylene ones go like balloons on hot days but dont leak the gas from the volatiles that make petrol go bad when they are gone..
Just to revive this thread as I'm curious about whether I need to put an additive in my tank. I just fired up my petrol powered strimmer and the plastic fuel pipes were leaking. It ran fine though. It had started off last autumn with maybe 1/3 tank which had all drained away. Was it the ethanol fuel I left in ? I'm beginning to think not. More likely the conventional problems of phase separation that have been talked about for a long time. Any road (good Yorkshire expression that), it's near impossible to get any proper information on what goes into an ethanol stabiliser. One site tells us it's mainly mineral oil and also that ethanol is beneficial as it absorbs moisture thereby avoiding corrosion. Hmm. I took samples of fuel and tested them for water content using a brake fluid tester. This measures conductivity and reads out in % water. In brake fluid up to 2% water is acceptable according to the device. Neither of my fuel samples had any water indicated. A sample of 10 year old brake fluid was just about on the line. I'm not planning to add any fuel stabiliser to my bus, unless there is strong evidence for it. I think the oil companies would be adding it already if required. And I suspect it would be massively cheaper than the brands I've costed up.
Mike over at Way Out Westie has written about this. LINKY It's an interesting read but only you can decide what's right for you.
Many thanks. Like Wayout Westie, I'd done some costing on additives and the Lucas stuff comes out cheapest at about £1.84 a tankful. The hardest thing to determine is whether it does any good. My grandpa used to put a shot of Redex in whenever he filled up - it was sold as an upper cylinder lubricant, but he could never tell whether it was worth it. He only added it because the man he bought the car off had used it before him.
