free hit
counters
Leaking Carby - Fuel System/Carbs - The Lotus Forums Jump to content
Sign in to follow this  
robertcosta

Leaking Carby

Recommended Posts

Help!

Just fitted a genuine refurb kit to the twin turbo dellorto's but I'm getting leaking from what seems to be the top cover gasket.

The front Dellorto is fine but when I turn on the fuel pump the rear seems to overflow. Its definitely coming from the gasket.

Do you think its a dud gasket?

The refit kit is a real one for turbo from Dellorto UK.

I've checked the fuel regulator and pressure is OK.

I swapped the top cover with a spare I had but still leaks.

When it begins to overflow I've whipped off the to cover and the fuel level is OK.

...webers weren't like this!

Robert


Robert Costa
1984 Turbo Esprit
Very Black!
2004 Lotus Elise
Quite Green! gone :-(

1977 S1 Esprit, in bits

1998 Lotus Elise S1, Azure Blue
Sydney, Australia

“The parts falling from this car are examples of the finest British craftsmanship”

Recommended procedure before taking on a repair of Lucas equipment: Check the position of the stars,kill a chicken and walk three times clockwise around your car chanting:" Oh mighty Prince of Darkness protect your unworthy servant.."

Share this post


Link to post
Share on other sites

Upgrade today to remove Google ads and support TLF.

Hi

If its leaking from the top cover then the needle valve is not seating correctly (i.e the pointed bit of metal lifted by the float). In normal service the carb is only about 2/3 full of fuel.

The carbs are also supposed to be airtight on the turbo cars, but its no real suprise that the top gasket will leak if its being exposed to full fuel pressure. i.e its not likely to be a problem with the gasket.

So, take the top cover off and dismantle and clean the needle valve and seat (there is probably a bit of crap on valve seat)

NB its also possible the needle valve may be nylon, not metal, but its still the pointed rubber tipped valve!

cheers Steve

Edited by 910Esprit

Share this post


Link to post
Share on other sites
Hi

If its leaking from the top cover then the needle valve is not seating correctly (i.e the pointed bit of metal lifted by the float). In normal service the carb is only about 2/3 full of fuel.

The carbs are also supposed to be airtight on the turbo cars, but its no real suprise that the top gasket will leak if its being exposed to full fuel pressure. i.e its not likely to be a problem with the gasket.

So, take the top cover off and dismantle and clean the needle valve and seat (there is probably a bit of crap on valve seat)

NB its also possible the needle valve may be nylon, not metal, but its still the pointed rubber tipped valve!

cheers Steve

Thanks Steve,

The needle valve and seat is brand new and come as part of the rebuild kit. I guess it could be faulty.

I've had that top cover off more times than i can remember over the last few days!!!

Is there any adjustment to the way the float and the valve works other than adjusting for 15mm as in the workshop manual?

Im thinking its not closing/opening properly for reasons other than dirt in the seat??

Robert

Hi

If its leaking from the top cover then the needle valve is not seating correctly (i.e the pointed bit of metal lifted by the float). In normal service the carb is only about 2/3 full of fuel.

The carbs are also supposed to be airtight on the turbo cars, but its no real suprise that the top gasket will leak if its being exposed to full fuel pressure. i.e its not likely to be a problem with the gasket.

So, take the top cover off and dismantle and clean the needle valve and seat (there is probably a bit of crap on valve seat)

NB its also possible the needle valve may be nylon, not metal, but its still the pointed rubber tipped valve!

cheers Steve

Thanks Steve,

The needle valve and seat is brand new and come as part of the rebuild kit. I guess it could be faulty.

I've had that top cover off more times than i can remember over the last few days!!!

Is there any adjustment to the way the float and the valve works other than adjusting for 15mm as in the workshop manual?

Im thinking its not closing/opening properly for reasons other than dirt in the seat??

Robert


Robert Costa
1984 Turbo Esprit
Very Black!
2004 Lotus Elise
Quite Green! gone :-(

1977 S1 Esprit, in bits

1998 Lotus Elise S1, Azure Blue
Sydney, Australia

“The parts falling from this car are examples of the finest British craftsmanship”

Recommended procedure before taking on a repair of Lucas equipment: Check the position of the stars,kill a chicken and walk three times clockwise around your car chanting:" Oh mighty Prince of Darkness protect your unworthy servant.."

Share this post


Link to post
Share on other sites

Hi

There is only one place fuel enters the carb and only one thing that stops fuel entering the carb - the needle valve, so either the float is not lifting the needle (because its stuck or it doesn't float!). The other possibilities are that the needle is not sealing on its seat or the valve seat is not correctly fitted to the top cover - There are no other options!

perhaps try swapping the float assemblies and the needle valves from carb 1 to 2 and see if the problem moves or stays in the same place. Cant really suggest much else, as there are so few possibilities!

To check the float hight, have the top cover placed vertically in your hand with the float hanging down under gravity - then measure the top of the float to the gasket face of the top cover

cheers Steve

Share this post


Link to post
Share on other sites
Hi

There is only one place fuel enters the carb and only one thing that stops fuel entering the carb - the needle valve, so either the float is not lifting the needle (because its stuck or it doesn't float!). The other possibilities are that the needle is not sealing on its seat or the valve seat is not correctly fitted to the top cover - There are no other options!

perhaps try swapping the float assemblies and the needle valves from carb 1 to 2 and see if the problem moves or stays in the same place. Cant really suggest much else, as there are so few possibilities!

To check the float hight, have the top cover placed vertically in your hand with the float hanging down under gravity - then measure the top of the float to the gasket face of the top cover

cheers Steve

There must have been something subtly wrong with the new needle valve 'cause I swapped it out with the old one and ..guess what..no leaking..go figure!

Robert


Robert Costa
1984 Turbo Esprit
Very Black!
2004 Lotus Elise
Quite Green! gone :-(

1977 S1 Esprit, in bits

1998 Lotus Elise S1, Azure Blue
Sydney, Australia

“The parts falling from this car are examples of the finest British craftsmanship”

Recommended procedure before taking on a repair of Lucas equipment: Check the position of the stars,kill a chicken and walk three times clockwise around your car chanting:" Oh mighty Prince of Darkness protect your unworthy servant.."

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...