condensation in fuel tank

You can be running te risk of rotting out the bottom of your fuel tank

Mike

Hi George

I don't think water in the petrol tank is the cause of your white smoke, most engines, (bikes and cars) emit quite a bit of moisture (condensation) when the engine is cold from the exhaust, and it should disappear when the engine is up to running temperature. If it persists when hot, it could be excessive oil consumption, (what color is the spark plug after a run?).

My M50 always goes better on a dull day when the air pressure is higher. After the Austrian rally when I went up the Grossglockner pass (two up! 2500mtrs) It didn't pull quite as well, because of the lower pressure.(or could it have been because my wife was on the back!!!!)

Try and run on fuel with no ethanol in and you will help remove all water from the tank, If you had a lot of water, the bike wouldn't run anyway, as it always tends to separate, and goes to the bottom, then causes the tank to rust.

Regards John O

I thought one of the criticisms of ethanol (misplaced in my view) was that it actually held water in suspension (or maybe solution)? So wouldn't that just allow it to pass harmlessly through the engine?

But where does this water come from anyway?

I remember when there were water injectors on the market which were supposed to increase performance. Cold damp weather should indeed increase the weight of charge going into the combustion chamber and enhance performance, even if only minimally.

I don?t know much about modern aircraft engines, but the transport aircraft I worked onin theRAF used water-methanol injection ( the methanol was only for anti-freeze ) to increase power on take off. The water, if any, in the tank comes from condensation ( like dew ).

It has always been known that engines developed more power when it was foggy but because it was foggy you couldn't take advantage of it. The reason for the extra power was that hydrocarbons in the fuel are normally un-burnt and pass out with the other products of combustion. By adding water vapour these hydrocarbons become combustible producing extra power.

In the 50's and 60's we would experiment with home made water injection systems (usually felt pipe cleaners stretched across the carb. bell mouth and fed from a small container of water strapped underneath) they did show small improvements but insufficient for the mess on required.

Dick

My old friend told me water injection caused engine internals to rust! (Not surprising, really!)

I do sometimes wonder about collecting some of those silica gel packets that arrive inside boxed goods, and putting them in a mesh basket (like a tea infuser) and hanging it inside the top of the tank when the bike is in the shed (in such a way that it has to be lifted out when re-filling.) That might reduce winter tank corrosion. But I always put an old towel over the tank when in the shed to prevent condensation both outside and (hopefully) inside.

As for water with ethanol in fuel - the allegation is that first it takes water into solution, and then the water separates back out and sits at the bottom of the tank. Problems are worst in places with hot, humid climates, where boats (in particular) suffer. GRP tanks are dissolved by the stuff, and steel ones rust. Madness!

I put a strip of masking tape over my filler cap breathers and this seems to stop the evaporation of the volatile elements and the constant movement of moisture laden air. The temperature remains fairly constant . The slight pressurisation this causes can make taps leak,so i check regularly.If you move bikes around then the vents need to be open.

George,

I was never any good at physics, I am just pleased my slow progress up the Grossglocker, can be blamed on atmospheric pressure and not my passengers (and my) weight.........Ha Ha.

Esso supreme (plus) doesn't contain ethanol................at least not in Yorkshire!

Regards John O

Having attended the Colombres Rally, (4 times) in Spain, I can certainly confirm loss of power at higher altitudes. Some of the runs, into the mountains, were over 2,000m. above sea level. The poor Dominator was gasping for breath!

Previously George Phillips wrote:

Next time you're out you can get me a few gallons, John. As far as I know Cornwall (or at least my part of it) doesn't stock Esso Supreme (plus). Have you ever read "Zen and the Art of M/cycle Maintenance"? Heavy going but in the book he explains how he had to re-adjust his carb as he went up into the mountains 'cos of the reducing air density. Out of interest the air density at 2500 m is 73% of that at sea level so your engine is pulling in 27% less oxygen into the c/chamber hence your M50 not pulling so well.

George

Funnily enough the book was an answer in the telegraph pub quiz today,.... nailed that one!

Previously ian_soady wrote:

I thought one of the criticisms of ethanol (misplaced in my view) was that it actually held water in suspension (or maybe solution)? So wouldn't that just allow it to pass harmlessly through the engine?

But where does this water come from anyway?

I remember when there were water injectors on the market which were supposed to increase performance. Cold damp weather should indeed increase the weight of charge going into the combustion chamber and enhance performance, even if only minimally.

My understanding is that Ethanol has an affinity for water. i.e it will draw water from the atmosphere. When the ethanol is saturated, the ethanol/water mix separates from the petrol and sits at the bottom of the tank. This mix is a weak acid.