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Flipper

Leaking carbs on S3

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Unsurprisingly my 87 S3 n/a failed its MOT on fuel leaking from the carbs and also emissions ....

Ive checked and both carbs leak from underneath its not pouring out but its enough and this is when the car isnt running.

Anyone got any ideas what the problem is ? and if not how easy is it to remove the carbs ...cos theres bloody tubing everywhere !

thanks in advance

Phil

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Not a direct answer but DON'T run it in this state. The distributor sits directly below the carbs, and fuel leaking from the carbs on to the distributor is the No 1 cause of Esprits going up in flames, as the sparking in the distributor ignites the leaking fuel.


Regards

Mat

post-1-0302470001278592957.jpg

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Agreed, don't run the engine with this kind of fault or you'll end up looking for a new car.

The carbs are relatively straight forwardd to take off and rebuild with a new gasket set.

Hilly


1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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Guest Troy Halliday

N/A cars are by far the easiest to work on having a great deal more space in the engine bay. To echo Mat's comments do not run the car until this issue is solved.

Removing th carbs is a relatively easy job. There are about 8 bolts holding the carbs onto the inlet manifold. 2 cables (choke and accelerator) and the two fuel connections to your carbs.There is also a series of vacuum tubes. Now if you were to do this job yourself take advantage of technology and photograph the carbs thoroughly so that you can see how all those vacuum pipes attatch.

However stripping down carbs and rebuilding them takes a little more knowledge.

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Thanks for the replies - and i hadn't much intention of driving it ....

seems pretty simple to take them off , and thinking that will reduce the eventual bill or point out the obvious its just wierd that they leak and being unable to see underneath can't see why or where .

i assume that i need to plug the fuel feeds to stop the flow and stop c**p getting into the system ?

and if i dont post again - you know what happened !

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phil, take them off and drain the fuel by opening and closing the butterfly valves, careful not to point at yourself while doing it(leasson learned by me!) you could then box them up and sent to troy to be cleaned out and rebuilt/setup

you can buy some inexpensive pipe clamps from any local motor factors to clamp the hoses.

also there are some pis of a little build i did on the top towers of mine as they were gummed up and sticky, link here : http://www.lotusespritforum.com/forums/ind...amp;#entry91638

Edited by bigsi

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When they are leaking underneath, it is usually the diaphragms (new ones are included with rebuild kit). Like everyone else said, the carbs are simple and straightforward. If you are handy with a screwdriver, doing it yourself should be straightforward and rewarding.

Two more words of caution:

1) You will need to remove the floats to replace the gasket. Remvove the floats by gently sliding the pivot pins out the side with a slender punch or other type of tool. Do NOT try to widen the tabs that the pins slide into, even though there is a notch there, and you may be tempted to slip a screwdriver in.

2) Be careful not to overtighten the carb-to-manifold bolts when you reinstall, so the O-rings don't squeeze out/in.

Have fun with the carbs -- they will be a rewarding afternoon at the workbench! :animier:

Edited by Tony K

Tony K. :)

 

Esprit S1s #355H & 454H

Esprit S2.2  #324J

1991 Esprit SE

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I had to do mine, when I did my HC engine conversion., had the same problem, leeking from under neath the carbs. I have loads of photos, which does help when putting it all back to gether again. It turned out to be an easier job to do than I thought it would be. Seal kit cost me about


The need for speed can be found with a Lotus

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where do i get the deal kit from ?

bell and colvill are literally down the road but having had a manifold change there once im not minded to use them again.....

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I think most speacailist so them like SJ sports cars or PNM. I got mine of Ebay. I will dig out details when I get home tonight.

Daz


The need for speed can be found with a Lotus

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Hi Flipper,

I've had the same problem with my S3 N/A and that was after rebuilding the carbs completely just as shown in Bigsi's link. The problem for me was the Dellorto pink rubber gaskets supplied for the bottom housing, they didn't compress and on the bench they dumped a full float chamber over five days. Many people on the lotuselan.net forum have had this problem but Dellorto/Eurocarb refuse to accept their gaskets are at fault. I made proper ones out of thin cork sheet and they've not lost a drop of fuel since. Check to see whether you have the dreaded pink rubbers and whatever you do don't use them to replace what you currently have.

Best wishes,

Si

post-3569-1194531574.jpg

Edited by jetace25

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I'm planning on rebuilding mine soon. What have you guys used to clean them and make them sooooo shiney?

Pete


Pete '79 S2

LEW Miss September 2009

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Nice work Jetace your carbs look nice and shiney. Ive got my carbs in a box under my bench at work with me ready to be worked on. How did you get the aluminium and mazak so bright?

Cheers Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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I polished mine up like that when I did the 912 rebuild, looks cool when you fit them, but it doesn't last long unless you continually clean them :animier:

Hilly


1981 S3 4.2 V8 6 speed (The Mutant)

Mutant V8 Conversion Thread

Knowledge is power .................... apparently.

 

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Thanks Buddsy,

I used wire wool on the intake and carbs and perhaps a little autosol on the carb bodies thereafter. Every little bit was cleaned or renewed and it looked great (I even adjusted the pump jets to deliver the textbook volume over 20 squirts) but guess what - Hilly is quite right they don't last long at all and keeping them like that is a losing battle....

...at least I have the pictures,

Si

Whilst it was apart I polished the inlet tracts smooth, it was surprising what a rough sandcasting it was with lumps all over the place. Good for an extra 1BHP perhaps? :thumbup:

post-3569-1194637596.jpg

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Ian ,it look kike it,s youre diaphrams leaking.Phone SJ sportscars he can supply just the diaphrams if that is all you need.I did mine on my S3 last week,I took one carb off and did one in situ I think it took about an hour and a half.Paul G...

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Nice setup Jetace - you have to spill the beans on how you did this - car-show quality finish! :thumbup:

Iain

...ooops, there it is :blink: (I just woke up...)

Edited by iainskea

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Well after much mumbling the carbs came off and the bottom bits are serviced.

However im nervous of the float assmbly - the pin needs to come out of the float - im assuming a suitable drift is the way to go - are these things handed and is there a simple way

Appreciate all the help thus far - thanks

Phil

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Phil

I've just put some phot ref my Carbs.

The float assemble shouldn't be a problem. there is a gap in one of the brackes for the float retaining pin, just gently prise this appart with a small screw driver, & the pin should slide out.

Daz

Edited by USAndretti42
Removed quote

The need for speed can be found with a Lotus

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Thanks - worked a treat .

Carbs are back on (easier than they came off ) not yet started her up again as the choke cable is a bit knackered and i want to make sure its tightened properly .

The 8 nuts are tightened and im guessing that they dont need to be really tight "just" tight enough to ensure a decent seal ....

to all of you thanks for the patience and help .

Phil

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There is a recomended gap size for the Carbs to inlet manifold. not sure what it is top of my head, but its in the service book. You don't want too tight as you will distort the 'O' rings.


The need for speed can be found with a Lotus

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If its the save as a T3 turbo with the 'fat' o-rings, I use the edge of a 2p coin which is in tolerance and can be used to check both the tops and bottom of the carbs without too much difficulty.

cheers Steve 84 turbo

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