How to Fix Fuel Leaking From Carb

[Chambers]

After showing off my car today to a friend he asked to have a look under the bonnet. With pride I flipped it forward to be greated with the smell of petrol and notice it was leaking from near the carbs.  I drove it home with the smell in the car itself and checked again, the fuel seems to be leaking from the cylinder bit at the front of the carbs (circled in the picture, it has the black pipe going into it). It stopped soon after I parked up but still thats not the point, its isnt fixed lol

Heres a pic to show where it is leaking. Any help you can give to how to fix it would be great.

Thanks

[Chambers]

From looking around it seems these are the float bowls that are flooding but Im not sure how to fix it. Is it a case of new seals and an overhaul kit or something other?

Any help would be great

[James]

Likely to be blocked float valves - take off tops of the float chambers off have a check. Blow through where the fuel goes - turn them upside down and lift the float up and down.

[Chambers]

Thanks its only coming out of the one but when I service the car next week Ill take off the carbs and have a look.

Ive ordered an overhaul kit as a just in case but if it is simply blocked floats it means I have it as a future job to do :-)

[drofgum]

Chambers,
James is most likely right; you probably have a small bit of dirt in the float valve. Do as he says; remove the top of the float bowl and blow through the fuel inlet to dislodge the dirt. No rebuild needed, but you should look to the fuel filter as it should have caught the dirt.
                                                                                             Cheers,
                                                                                             Paul

[Chambers]

Thanks, I assume I will have to fully take the carbs off to do this?  Also if I take the carbs off I woiuld have a load of fuel leaking will I, just whats already in the pipe after the fuel pump?

[James]

No need to remove the carbs - just 3 screws.

I'd change your fuel filter also.

If you get the issue again - then remove all the fuel lines in the engine bay and blow them through - and replace the filter.

(I assume you have a fuel filter? should be before the pump)

[CHRIS211083]

Where abouts are you in the country??????

[Velocita Rosso]

If it was me I would buy a couple more needle valves for the floats , for what they cost

Sometime s if old ,they wear and stick on the nylon walls or the brass cone could be worn
http://www.burlen.co.uk/

[greenbonnie]

or better still use the grose jets from moss. i have these on my car work great. only £7 . they use a ball bearing to shut the fuel off. much more reliable. pete

[Chambers]

Thanks, Im in Darlington (North East).  Ive got a fuel filter on the way should hopefully be here tuesday-wed also have a carb overhaul kit coming which will sit in my spares box lol

Also can someone photo the 3 screws, chances are I will take off the wrong ones lol

Not sure what grose jets are, can someone explain fully to a dummy

Thanks

[James]

Don't worry about grose jets for now - I doubt you'll need them and a lot of people have more issues with them.

Your carbs have two main parts - the body (with big dome bits on top) and the float chambers either side.

The float chambers are where the fuel comes in - the you'll need to undo the fuel hoses (be ready to block them with a bolt etc) and then there are three screws to undo.


James

[greenbonnie]

hi grose jets completely replace the standard needle type. that on the inside of the float lid. with the three screws you have to take off. pete
or just look on www.moss-europe.co.uk

[Chambers]

thanks for the help guys, lets see how it all goes :-)

[Chambers]

Well I cleaned out the float bowls and it would seem when I got home that fuel is still coming out.  As mentioned in a different thread I have very poor mpg and it was mentioned that the carbs could be running very rich.  Could this cause the fuel to be coming out and how I could fix it.

I think my next step will be to completely take the carbs off and give them a good full clean with carb cleaners see if that helps?

[willcolumbine]

Have you fitted a new fuel pump recently? The new ones produce waaaayy too much pressure and, without a regulator, the carb can't shut the flow of fuel off.

[James]

You shouldn't need to take them all apart at all - the leak from the float chambers should be very simple to sort out.

What fuel pump do you have? Have you checked the fuel pipes that they are not split and that hose clips are tight enough?

[Chambers]

The hose clip that I took off today is quite tight I didnt want to over tighten it, as for the fuel pump I have no idea if it has been replaced as the car is new to me is there any way I can measure the pressure of it simply?

[willcolumbine]

Take a picture of it! The new ones look a bit different to the old ones!

[Chambers]

Picture of the fuel pump (I think)

[James]

I do seem to remember there were issues with new pumps putting out too much pressure - which would give you the issue you have - but have no idea if that's a new pump or not.

[Nick Moore]

Richard, if the float chambers are overflowing, it's not a tuning issue, and the carbs don't need to be removed. Possible causes are:
- excessive fuel pressure, so that when the valves in the roof of the float chamber close, fuel is forced past. That photo is your fuel pump, and it looks like a replacement. The easiest solution is to fit an original.
- second reason is that the valves in the roof of the float chamber are worn, so that they don't stop the flow of fuel when the float rises. Solution - replace, either with new original-type ones or the Grose Jets. I'd stick with original (Triumph knew best etc...)
- lastly, if the floats are set incorrectly they may not be shutting the valves at the right fuel level. Or they may be leaking at have fuel in them.

At least, those are the three easiest fixes. Happy tinkering!

[Chambers]

Thanks for the reply, can you explain how I can check if the floats are worn and also where I would get replacements, and before I check they are worn, how I check that they are set correctly?

Ive just had a further look and it seems that the fuel pump I have looks very much like the Haynes manual's page 90 (early type fuel pump)

so could be the floats?

[willcolumbine]

Sorry, I got distracted watching 'the inbetweeners'! That's looks to me like a replacement pump so it's very likely to be chucking out about 5-6 psi. You can get a pressure guage put it in the line between before the carbs to check. Su's need about 1.5 - 2 psi.

[Chambers]

cool I'll order a pressure regulator now but I thought it was the standard one :-s