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MG MGB Technical - Weber Carb Problems

Have weber carb and find that after driving for a while and the car is hot, if I turn it off , cannot start it again until the engine has cooled down. Also if the car is unused for a period of time that the gasol;ine has drained from the carb !!!!

Kim R.
K Rutherford

Kim. What model Weber carb? What intake manifold are you using? What year of car? What exhaust system are you using? What fuel pump are you using?

All of this would be of assistance in trouble shooting your problem.

For my own two cars, I am running the Weber DGV with the TWM intake manifolds, SU fuel pumps with one car having a Peco header and the other car having a stock chrome bumper exhaust system. Neither of these vehicles, nor my daughter's 77 which is similar, have the problem you are describing.

Les
Les Bengtson

Thank's Les for your reply. The Weber carbs I mentioned are twin DCOE40 side drafts, one barrel feed directely to each cylinder , distributer 25D Lucas and pertronix Ignition. These are fitted to a 67 Lotus Elan belonging to a friend of mine and I had hopes of helping him out with our excellent MGB site
Kim R.


K Rutherford

It's more than likely fuel percolation. The residual heat in the block and exhaust manifold is evapourating the fuel either in the float chamber or the fuel line or both. Give the carb and fuel line some heat sheilding and put an insulating spacer between the carb and manifold.
Allan

I agree with Allan. I have a DCOE45 on my B. I don't get the the first problem but I do get the second problem that you describe. I have done nothing to sort that except keep the key turned for a lttle longer if I have not used the car for a while.
Doug E

Hey Kim,
I have an Elan in addition to an MGB with a DCOE Weber. Although my Elan has Strombergs. I don't think its a vapor lock problem at the carb since the exhaust is on the other side from the carbs but it might be vapor locking in the pump itself. The Elan uses a mechanical fuel pump underneath the carbs that has a glass dome top on it. These things are often weak and tend to leak very easily. A leaky fuel pump might be siphoning the gas back out of the carbs. You might try fitting a low pressure electric pump and see if that helps any.
How hot is the elan getting when it won't start. My is capable of getting plenty hot, if its getting to hot it could actually be more of an issue with the head sealing properly and giving good compression. The last thing I was thinking was to check the needle valves to make sure they are shutting ok, and the floats to make sure they aren't full of fluid. If either is the case the motor might be flooding right after it shuts off, although this would likely happen when it was cold as well.

Just a few options for you to consider.

Also try www.lotuselan.net as a good resource for vintage Elans.

Good luck. Glad there is another lotus enthusiast on the board.

-Bill
Bill Mertz

This thread was discussed between 05/10/2008 and 14/10/2008

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