Thread: E10?

John is on the money honey

And the crap eats more than rubber, it eats some old carburettor bodies as well

Originally Posted by V8Ian

Air has to replace used fuel so moisture bearing air is being drawn into the tank.

no,, is why the caps are pressure rated, is why you get air pressure release when cap is undone.


yes I understand about the absorbment into the fuel,,
and it is irrelevent in modern cars,,

Originally Posted by Pedro_The_Swift

all modern fuel systems are closed.
have been for a long time.
so e10 can only absorb whatever air is in the tank, none from outside.

yes they sometimes VENT to the atmosphere(one-way pressure release),,,
usually on very hot days
like LPG tanks,, except not so explosively

I'm afraid you are not strictly correct. They do not allow outward venting, except, as you point out, to relieve excess pressure when hot. But they must allow inward venting, as otherwise, by the time the tank was empty, it would have a pretty good vacuum in it, and fuel delivery would be difficult!

The air that is drawn in will contain water vapour, which will be absorbed by the ethanol. If the tank is only partly filled, cool temperatures overnight will mean more air will be drawn in, which will then expend during the day, probably requiring pressure relief, and the cycle repeated next night, with fresh, moist air.

The only way to avoid this is to keep the tank completely full.

As I pointed out above, if there is no ethanol in the fuel, if the air is moist enough, and there is a sufficient temperature cycle, the water vapour in the air will condense on the cold top of the tank, from where it will run to the bottom of the tank. Since it is immiscible with and denser than petrol, it will form separate droplets in the bottom of the tank, that cannot progress further into the fuel system, and hence are largely harmless, although owners of Series vehicles with rusted out fuel tanks or rust pinholes in the suction line may not agree!

In a modern (?... since early 70s) petrol car system the vapour pressure in the tank gets vented through the carbon canister to atmosphere. Theoretically that scrubs out all of the volatiles and nasties. The engine draws from the carbon canister at times low load, high vacuum) and essentially recovers this vapour and burns it. So, yes, strictly not "fully sealed" as I previously posted. I had my emission hat on. True that the tank draws in ambient air as the level drops or it cools, via the cap typically, but some via the carbon canister.
However none of this is hugely relevant to an old JD mower which just has an equalising pin hole in the cap (or one way valve in later stuff) and not much else...
E10 won't eat metal and is likely more beneficial than harmful in general. Holds the moisture in suspension and stops it pooling and coming through in slugs, or rusting your old tanks... also cleans the system. You need to get up a lot higher than that before that's remotely a concern for poor grade metals and 50%+ for anything decent (OEM). For E85 we needed to change rubber composition, change gal steel to stainless, and fit fuel composition sensors for engine tuning. For E10 we did nothing all. That was on a late model car sold globally.
It used to be recommended that you add a cup full of metho to your full petrol tank regularly, esp for outback travel. Back in the days of steel tanks and carbies. Call that about 0.5%. Low concentrations are safe and beneficial. High concentrations require reengineering to work properly and reliably. Where that tripping point is depends on how the engine and fuel system was built and specified.

My 45L side PULP tank is (assumed ) mild steel, it pops and bangs regularly

...and so....getting back to the question......my ride uses e10, its not a John Deere, the engine is 38hp Kholer . My neighbour's is a Husqvarna , similar power and he uses e10. Do JD make their own engines?

i wont use e10 in any of my cars or chainsaw. it's just not fuel.