Ethanol in fuel carbs take a look

[andrewh]

I have just stripped these strombergs which were running really well, but leaking through the bottom O rings. The white plastic plugs are also cracked and need replacing. Do we think this is ethanol or rust? The filter was quite clean when I changed it so makes me think its ethanol which would go through the filter rather than rust which would presumably be caught.

[DWW]

Have you been using e10 or e5 petrol?

[andrewh]

I don’t think i have ever put E10 in for obvious reasons.

[DWW]

At a closer look it doesn't look like rust, it looks too dark, does it feel greasy or oily?

[andrewh]

I shall check but I am minded to think it’s years if fuel residue

[MarekH]

That's exactly what it looks like.

For a car that spends a lot of time laid up, the lighter fractions evaporate out and the thicker (and eventually sludgier) remains remain.

The water jacket behind the carburettors has a pocket where the thicker elements of fuel condense down to during startups. This eventually gets evaporated on a long run but you'll often see evidence of a thick reddish liquid in there aswell.

Ethanol in fuel would eventually manifest as a sludgy imiscible waxy jelly. What you typically see isn't actually ethanol, but the constituent components of the petrol blend after they have started separating out of solution.

kind regards
Marek

[gtjoey]

Welcome my friends to the world of Ethanol GAS.....
IT WILL DESTROY IT ALL AND YES the goop is the residue from the moisture and the gas....
Its terrible, unless you fill and run it out , its the worse thing for old cars.
ps check your gas filter you will notice it will swell with the water in the line

[andrewh]

Thank you Guys. I have established that there is some residual rust in there since its magnetic! However, I am not altogether surprised as the tank/pipes will no doubt have some internal corrosion. Surprised that the filter lets so much through and wondering if its worth putting another inline filter in place. Anyone got any ideas on a filter that is better at catching rust from entering the carbs? The only thing I would say is that the car was running extremely well other than leaking through the bottom O ring in the fuel bowl, which says something!. I am not sure what though. It should run a lot better with this crud removed. Meanwhile, its Esso Synergy only from now on.

[Jeremy]

Anyone got any ideas on a filter that is better at catching rust from entering the carbs?

I'll tell you what else is helpful in keeping rust out of the carbs Andrew: disconnecting the breather pipe from the air intake plenum. Angus's boys discovered some minute fragments of rust in one of the intakes on mine when they were servicing it - and since the air filter drum is immaculate inside, it had clearly come from the corroded interior of the breather pipe. I now have the engine venting through a hose down onto the road and the hole in the intake blanked off. Result: no more rust, water vapour, oil fumes and other crap entering the carbs. Fringe benefit: engine has stopped leaking oil onto the garage floor, which was presumably due to crankcase pressure from the (constricted) breather.

Angus made the same mod to his car and his engine has stopped leaking too. He is working on a catch tank design.

You might want to check the state of your breather pipe?

[Allrand]

It should run a lot better with this crud removed.

Don't be disappointed if it doesn't, if it was running well before, it'll coninue to run well. Performance will only be affected when crud starts to block jets, airways or float valves etc.

[andrewh]

Thank you for the advice Jeremy. I shall certainly take a look at that. There is little doubt in my mind that a lack of use of these cars is a large part to blame for these problems as well , of course, the ethanol .