Help! Slight fuel leak but engine still runs.

[fhwlloyd]

Update - leak seems to be coming from an overflow pipe off the second carburettor. Could it be a block in the carb?

Hi everyone, I've just made it to Val D'isere and noticed some misfiring. Upon stopping I've spotted a fuel leak coming from ended the car. It's not clear where it is originating from and I'm tentative to start the car again.

I've put in a call with the road side assistance on my insurance and they're sending someone. However, what's the best way to checking and resolving this? Is it probably ok to start the engine to try and identify the leak when running?

NB- I'm not a technical guy and I thought I had done all I needed to when I had to change a tyre in Tuscany!

Henry

[Hugo]

Two possibilities; either the float needle-valve is leaking on that carburettor or the float has sunk. Try giving it a few taps with a spanner on the lid of the offending carb. If there's a bit of dirt lodged in there you might just dis-lodge it & stop the leak. Better still, pop the lid off the float chamber & see if the float is still floating or whether it is now floating at the bottom of the float chamber! If the float is ok, blow through the fuel inlet while holding your finger over the float needle-valve to see if it is shutting off. Should be an easy fix, but ultimately I would replace all float needle-valves and / or floats, depending which is at fault.

[Hugo]

By the way, I wouldn't be too alarmed about a bit of gasolene leaking, so long as there are no ignition sources anywhere near. Diesel actually ignites at a lower temperature than gasolene, by gasolene is of course much more volatile, so any spark will ignite it without a second thought, whereas you can throw a lighted cigarette into a tank of diesel & it will just go out (I know because I had a girl working for me who tried it on one of my coaches!). One thing you should be very careful of is the engine spitting back through the carb if you have gasolene lying about with the air filter off. I set fire to a van like that once

[Heuer]

As Hugo says the float needs adjusting or replacing if it has leaked. It could also be a split diaphragm. Read the manual on servicing details: https://www.dropbox.com/s/67d95m8bt2b6j ... l.pdf?dl=1

If the overflow pipes are fitted correctly they will be held in place by a bracket that routes them well away from the dizzy. I assume your car is fitted with SU's?

As for testing the carb should leak with just the ignition on. The fuel pump will keep running as long as the carb demands fuel which it will continue to do so if the float does not rise to the correct level. If you can't do the job yourself you need to find a competent garage who understands classic cars. Maybe Hubert's map can help? Failing that we need assistance from one of our French members. The E-Type map will tell you if there is anyone local to you.

[Hugo]

Whatever you do, don't make the same mistake I did many, many years ago; - On my way back to university in an old Ford Pop, I noticed it was running rich. The float had a tiny pinhole so I got the petrol out and soldered it up. Then a hundred miles down the road, the float started sinking again. I had the bright idea of burning the petrol out of the float so I could continue my journey, so I lit it, & got a nice little flame. Great, I thought, then, as the float got hotter, the little flame turned into a jet, and then a bloody great flame thrower. By now the float was too hot to hold, so I dropped it, & it bounced off my shoe, setting fire to my foot in the process, and rolled out into the road, right into the path of a 38 ton truck, which promptly flattened it. I still have that squashed float somewhere!

[Series1 Stu]

Remember also that the starter motor is below the carburetors and can give sparks when it's turning over the engine. Take care and keep a fire extinguisher close to hand.
Regards

[Mark Gordon]

Hugo, you can't make this stuff up! I know it wasn't funny at the time, but now it's hilarious.

[fhwlloyd]

Thank you for all the advice on this... When I went away to do my research inside to get on the wifi (post on the forum, flick through my haynes manual etc) I left the roadside assistance chap with the car. He decided to block the overflow pipe and flood the engine . I'm not technical but even I knew it wouldn't be a good idea to block it. Anyhow, eventually got everything sorted and made it home. Thanks again and in the future I will, stop, breath, discuss on the forum, check for garages, check my spares etc before doing SOS to insurer.