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View Full Version : water in my petrol (gas) and ethanol?



profloater
2013-Aug-09, 07:35 PM
My car has been suffering from symptoms very like water in the petrol but when I sampled the tank with a small bore suction tube there was only a little water like 1cc. However I noticed when I shook the container it disappeared! Now I read that with some ethanol in the gas, as they now tend to provide, the ethanol is hygroscopic and the petrol can now dissolve hundreds of times more water and furthermore if the petrol changes temperature, the water can come back out as water in the carb. This is a fifty year old car with twin carbs. This is new to me. Does anyone have knowledge of this problem and what to do about it?

redshifter
2013-Aug-09, 07:41 PM
What kind of symptoms are you experiencing? Has the weather been warm lately? I ask because it occurs to me you could be experiencing vapor lock. As far as water in the gas tank goes, I believe alcohol will absorb/dissolve the water, but I'm not sure how much water it can take care of. How dirty is your fuel tank? It's possible you have rust/sediment issues in the fuel tank/fuel lines. Does your fifty year old car perhaps need higher octane fuel? I'm just brainstorming here, I hope it helps!

profloater
2013-Aug-09, 08:35 PM
What kind of symptoms are you experiencing? Has the weather been warm lately? I ask because it occurs to me you could be experiencing vapor lock. As far as water in the gas tank goes, I believe alcohol will absorb/dissolve the water, but I'm not sure how much water it can take care of. How dirty is your fuel tank? It's possible you have rust/sediment issues in the fuel tank/fuel lines. Does your fifty year old car perhaps need higher octane fuel? I'm just brainstorming here, I hope it helps!Hi this is a gentry, triumph straight six twin stromberg. Runs fine on unleaded. Symptoms are starts fine runs well but after 10 minutes starts to cought, gets worse, rest period will improve it again. I have new plugs, new coil, choke shuts off, timing good, carbs adjusted well. I read petrol normally will dissolve a few hundred ppm water but hundreds of times more with ethanol. Normal petrrol retains the water but apparently, allegedly, with ethanol the water can be released again. Trouble is this car is left for long periods unused. I guess I have to avoid the ethanol petrol if I can.

redshifter
2013-Aug-09, 08:47 PM
Hi this is a gentry, triumph straight six twin stromberg. Runs fine on unleaded. Symptoms are starts fine runs well but after 10 minutes starts to cought, gets worse, rest period will improve it again. I have new plugs, new coil, choke shuts off, timing good, carbs adjusted well. I read petrol normally will dissolve a few hundred ppm water but hundreds of times more with ethanol. Normal petrrol retains the water but apparently, allegedly, with ethanol the water can be released again. Trouble is this car is left for long periods unused. I guess I have to avoid the ethanol petrol if I can.

Nice car! I still wonder if perhaps you have rust/sediment in the fuel system, such that it runs fine until the rust particles/sediment have been stirred up and start working their way into your carbs. OTOH, I'd think the fuel filter would get clogged up enough that eventually it wouldn't run at all. Still, might be worth checking the fuel filter for rust and/or sediment, or draining the fuel tank if that's feasible.

publius
2013-Aug-10, 08:24 AM
My car has been suffering from symptoms very like water in the petrol but when I sampled the tank with a small bore suction tube there was only a little water like 1cc. However I noticed when I shook the container it disappeared! Now I read that with some ethanol in the gas, as they now tend to provide, the ethanol is hygroscopic and the petrol can now dissolve hundreds of times more water and furthermore if the petrol changes temperature, the water can come back out as water in the carb. This is a fifty year old car with twin carbs. This is new to me. Does anyone have knowledge of this problem and what to do about it?

That is a big problem with the ethanol blends. And it will actually pull water vapor out of the air when exposed. Modern emission control systems seal the tank to prevent vapor loss (purge when running) and a side benefit of that is the fuel in the tank isn't exposed to outside air as much.

When it separates, that water can do a lot of damage, messing up the carb of course (it's even more hell on the intricate high pressure fuel injection systems of diesels).

Unfortunately, this is just a problem with older cars and the newer ethanol blends. Keeping the tank full might help, preventing air space with water vapor to be in contact with the fuel. And ethanol can do damage to some of the "rubber" materials in the fuel system of older vehicles which aren't made for ethanol.

I've had terrible water in fuel problems over the years caused by my own screw-ups. I used to get gas (petrol for you Brits, of course :) ) and diesel fuel in a 55 gal drum with a hand pump which I would strap in the back of a pickup. Well, that drum developed a leak around the bung hole due to the metal fatigue caused by flexing when using the hand pump, and I left the thing out in the rain before I knew of the leak. Pumped loads of water into the fuel of a couple of trucks.

I had to drain the tanks and clean out the carbs. And then even then, I forgot and left that same drum out and did it again later. I then threw that drum away and got a new one so I'd never due that again.

They used to make some product, the name of which I forget, that was even better at dispersing water in fuel to help with this. I got it at the auto parts places I frequent which the owner recommended. It's some type of alchohol itself, with other additives.

profloater
2013-Aug-10, 08:40 AM
I fitted a fuel in line filter which still looks clean and my sucking the bottom floor of the tank brought up hardly any dust. What surprised me was that a little bubble of water that came up dissolved when a shook my bottle! I am going to keep it filled now and try to find pure petrol. The Gentry is a replica MG TF and the bottom of the carbs drain plug is really hard to reach, however that will be next. Right now I will try wide open throttle run to see if I can shift any water in the carbs. And I will keep the tank topped up. The problems started after a long idle period, through the last winter. Never realised ethanol would be such a pain.

publius
2013-Aug-10, 08:57 AM
The problems started after a long idle period, through the last winter. Never realised ethanol would be such a pain.

Bingo! It's amazing how much just sitting there can screw up vehicles. Something can be running perfectly and you let it sit for a few months (or even worse, a year+) and then it won't run.

But sitting idle, with empty air space over the fuel in the tank will do it, again especially with the older vented fuel systems. When it gets cool, some moisture condenses, and runs into the fuel. Then it heats up and the expanding air aided by fuel vapor pressure pushes vapor and air out of the vent. Then it cools down, and pulls more moisture laden air back in the tank.

And then that water sinks to the bottom of the tank and will start rusting the bottom.

Running it of course keeps things stirred and the little bit of condensation that develops each night doesn't matter. But let it sit, and it will make a mess.

profloater
2013-Aug-10, 10:18 AM
It also occurs to me that water in the carb bowl will mess up the float balance and tend to starve the carb and of course will not evaporate away since there is a layer of gas on top. However, it still runs well when cold. I will have to devise a special tool and get those carb drain plugs out.

novaderrik
2013-Aug-12, 07:43 AM
i've been (legally) driving for 23 years. we've had a 10% ethanol blend here in MN for at least 5 years longer than that.
cars are something i play with for fun and sometimes profit, and i can honestly say that i've never seen a problem that i would attribute to the ethanol on anything but 2 stroke motors.. i have noticed, however, that cars that you don't run for long periods of time run a lot better when they come out of storage if you run the carburetor or fuel rails dry when you run it for the last time... this gets the gas out of the lines and fuel bowls so there won't be a layer of additives left over gumming things up after the volatiles evaporate out of the gas over weeks and months.

regarding the way the Triumph is running: i'd pull the carbs apart to clean them up, as well as remove the fuel filter and use compressed air to blow out the lines... when you put it all back together, make sure the choke systems are properly adjusted and functioning as designed. also check the ignition timing, because it costs nothing but a little time of you have a timing light.

profloater
2013-Aug-12, 10:13 AM
As far as I can remember, I only filled up with a mixed gas twice for the long trip to France. I did find the choke cable was a little sticky and that was part of the problem, one carb runs slightly rich always, the jet adjuster is fully in. I filled up with regular petrol and ran around with high revs in second gear on bumpy roads (!) that has made it much better. Unconventionally I decided to reduce the contacts gap to increase the coil dwell time, I have an electronic ignition fitted, and readjusted the timing. It went much better and achieved max revs of 5000. It still coughs a bit when hot, don't know why, but maybe HT lead terminations? Going better and the plugs look good, I have done so many things now it is impossible to be sure what the root cause was, but I did not drain all my petrol away. Too thrifty perhaps. :)

profloater
2014-Jul-08, 07:46 PM
late notes: after many changes of spark equipment it seems to me the problem is still the old vapour lock caused by the ethanol in the petrol. The boiling point of ethanol is about 78 C and the water in my triumph runs at 75 indicated. It seems likely the under bonnet (hood) temperature rises enough to boil off the ethanol in the fuel lines causing a vapour pressure and a vapour bubble. The exhaust pipes also raise the fuel line temperature by radiation and convection on the carb side.

However I cannot determine if such a bubble gets back into the mechanical fuel pump or forwards into the carb bowls. Or somehow causes the float needles to resist the weight that normally lets the fuel in.

I thought it was just me but now I read that many older cars with carbs are having increased problems with vapour lock using unleaded fuel with ethanol. Normal petrol boils at 96 or so, so the lower BP of ethanol is significant.

I have a baffle between exhaust and input manifolds and some pipe insulation on the steel fuel line.

Last trip, the car stopped after about 30 minutes driving. It always recovers, given time, about another 30 minutes. Pain.

I will try switching to the higher octane premium fuels (98 instead of 95) but these have ethanol too! Next step, I will fit local temperature probes on the carb bowls to tie this problem down. Maybe I can add some kind of vent to cool the carbs.

Anybody else driving old carb cars?

redshifter
2014-Jul-09, 12:07 AM
My last carbureted car was a 1985 Honda Accord. It had a problem where in cool (say 40's F), humid weather it would run fine for a while (maybe an hour or so), then slowly lose power and eventually the engine would die. After waiting a little while (10 min or so) it would start up and run fine again until the symptoms returned. I sold the car before I diagnosed the problem, but I think what was happening is that as the cool, humid air was drawn into the carb, it would ice up (carburetor icing) and eventually the engine would die. Then, the hot engine would slowly melt the ice build up and then it would run fine until the ice built up again. I believe that Honda carb had a mechanism to prevent this but probably failed which then allowed the icing to be a problem. I had 237,000 miles on that car before I sold it - on its original clutch! 44 mpg on the highway too until the icing issue came up.

wd40
2014-Jul-09, 12:41 AM
20 years ago I saw two same model BMWs simultaneously stalled in a petrol station forecourt. It turned out that the manager had been adding 20% water to the petrol for years and getting away with it. But the then new computerised fuel management chips in the BMWs detected the petrol was sub-par and automatically shut down the engines of both cars at the same time.

In India fuel adulteration with water was once so prevalent, especially of paraffin, sometimes with fatal results in homes due to inefficient combustion, that they once even considered imposing the death penalty as a deterrent.

Presumably deliberate fuel adulteration in the US is today minimal, with hefty jail terms for violation?

Solfe
2014-Jul-09, 04:09 AM
Doesn't this car have a flip up, vented gas cap? Could there be water around the edges of the cap and when you run the engine, the cap pulls tight and the vents plug up? It could also explain the water in the tank.

I had this issue on a motorcycle... actually, the bike I am trying fix now.

profloater
2014-Jul-09, 08:01 AM
Doesn't this car have a flip up, vented gas cap? Could there be water around the edges of the cap and when you run the engine, the cap pulls tight and the vents plug up? It could also explain the water in the tank.

I had this issue on a motorcycle... actually, the bike I am trying fix now.Yes it does have a flip up fuel cap and I had not considered that. However the last time it stopped, I quickly pulled off the fuel hose at one carb and the petrol flowed well. However the car would not start. That would suggest that if it is vapour lock it is inside the carb. I wonder if ethanol also increases the risk of carb icing?

I am wondering if the vapour pressure can close the needle valve even with the carb nearly empty?

profloater
2014-Jul-09, 08:03 AM
My last carbureted car was a 1985 Honda Accord. It had a problem where in cool (say 40's F), humid weather it would run fine for a while (maybe an hour or so), then slowly lose power and eventually the engine would die. After waiting a little while (10 min or so) it would start up and run fine again until the symptoms returned. I sold the car before I diagnosed the problem, but I think what was happening is that as the cool, humid air was drawn into the carb, it would ice up (carburetor icing) and eventually the engine would die. Then, the hot engine would slowly melt the ice build up and then it would run fine until the ice built up again. I believe that Honda carb had a mechanism to prevent this but probably failed which then allowed the icing to be a problem. I had 237,000 miles on that car before I sold it - on its original clutch! 44 mpg on the highway too until the icing issue came up.That sounds like my problem, I wonder what to do next.

NEOWatcher
2014-Jul-09, 12:38 PM
I had a car with similar symptoms in the 80s.
It turned out to be a corroded (thus leaky) exhaust gas pulse air system. I put some of that muffler wrap around some of the worst tubes and it improved.
I guess it played havoc with the oxygen sensor.

I then traded it in (I was ready to buy a new car anyway) before I felt it was worth the money to replace. (a few months later, got a recall notice for it)

profloater
2014-Jul-09, 02:59 PM
This car predates oxygen sensors. It has the vitesse straight six 1500 engine, twin Stromberg carbs in fairly good condition. Running gear is 1967 MGTF lookalaike body is styled 1955 just before the MGA.

I am due to drive it to France tomorrow, I fitted a magnet ring to replace the contacts, retimed, lagged the fuel lines and jacked the bonnet open an inch for more air flow.
It is 2 1/2 hours to the tunnel (still having trouble since the tour de france train ripped out the power lines last Sunday) then about an hour in France all being well.

profloater
2014-Jul-10, 02:04 PM
Alas, I did not get far before losing power. It seems now the Strombergs' pistons are not lifting when the engine is hot. So it's a full strip down and to add insult, the battery is not charging. I am sure no one is interested but it helps me calm down to hit the keyboard. The diaphragms seem good, maybe the vent hole deep down is blocked. Another project for another day.

profloater
2014-Jul-26, 12:54 PM
Just for carb nerds, I may at last have it.
All my own fault.
I put multigrade oil in the dampers of the carbs.
My current theory is that the problem was not heat but just time. The carbs needle holder going up and down pumped out oil and it found its way to the little hole that allows the vacuum above the diaphragm. One carb suffered first, then failed to lift. That weakens the mixture because the throttle still opens.

I washed out the dampers with WD40 and actually slackened the top screws to make sure the pistons were lifting cleanly. Now it seems to go as it should. I broke the alternator wire while messing with the fuels lines so easily fixed.

Summer motoring resumes!

Trebuchet
2014-Jul-26, 03:46 PM
I actually had a shop refuse to work on my old pickup (much newer than your vehicle, and Japanese to boot) because it had a carburetor. When the problem was an oil leak. Apparently carbs are a lost art. (To be fair, I had asked for a tuneup as well.)

Solfe
2014-Jul-27, 12:14 PM
My sister is a real gear head and I recall several conversations between her and my mother about tearing apart carbs on the dinning room table. Our mother really disliked the practice.

Hlafordlaes
2014-Jul-27, 12:49 PM
Triumph straight six twin stromberg...

If you don't make it down to Barcelona with that dream machine (free tapas!), here's one guy who's gonna hold a grudge!

My Dad was into British small cars, but motorcycles were my thing. This is the bike (http://www.triumphmotorcycles.com/bikes/scrambler/2014/scrambler) my wife won't let me have. (She's right; I've got the stones, but no longer the bones.)

NEOWatcher
2014-Jul-28, 05:01 PM
I washed out the dampers with WD40 and actually slackened the top screws to make sure the pistons were lifting cleanly.
I'm glad you were able to work with a friend. Did he say anything about the engine being top heavy?

Trebuchet
2014-Jul-28, 05:53 PM
I'm glad you were able to work with a friend. Did he say anything about the engine being top heavy?

I am SO glad I was able to restrain myself from doing that!

profloater
2014-Sep-02, 08:02 AM
this post is strictly for petrol heads, but I think I finally got somewhere. I changed the ignition I serviced the carbs and still the car repeatedly coughed to a halt at twenty minutes. But the bowls of the carbs were cool. Finally I figured the air going through was getting very warm so I cut a hole in the side and added a kind of funnel to ram cold air in to the general area of the carb air filters. It seems to work and actually the engine seems to run better too on cold air (more density I guess) So I think it was icing due to the ethanol with warm air heated by the internal space.

JohnD
2014-Sep-02, 12:37 PM
Profloater! You have a Triumph engined Gentry!
I've raced Triumph six cylinder engined cars for twenty years!

You may have sorted the problem, and got lots of useful advice here, but a specilaist Triumph site may be useful to you.
The Triumph Experience is US-based: http://www.triumphexp.com/
And of course there are several, UK-based:
TSSC (board only just up and running after a devastating crash and a long hiatus): http://forum.tssc.org.uk/
TR Register (Sixes, mostly 2.5, but same engine): http://www.tr-register.co.uk/forums/index.php
Club Triumph: http://club.triumph.org.uk/cgi-bin/forum10/Blah.pl/
Sideways Technologies (Triumph-based, modification-heavy): http://sideways-technologies.co.uk/forums/

Bests!
John

PS But you ARE in the UK! And going to France via the Chunnel! Bon voyage!
PPS The earliest Vitesse, the '6', had a 1600cc straight six engine with twin Solex carbs. The next, the "2 litre", had - no surprises - a 2000 engine and twin Zenith Strombergs.
The final development into the 2.5 was never fitted to production Vitesses, or GT6s. J.

profloater
2014-Sep-29, 12:42 AM
I missed this post travelling. Yes I really like the straight six engine , beautifullyi balanced. In starting this server thread I came to realise how few carbureted cars are still around. I enjoy driving the gentry for the open air for the sound and for feelingof petrol pulling me up the hill, which is just not the same with the modern car. I am in the USA at the moment for a few weeks and I'm having louvres put into the bonnet (hood) of the car and when it is finished I will try and post a picture of it.