Lotus Elan

Leaking Fuel

PostPost by: mike+2s130 » Mon May 10, 2004 8:58 pm

i have fuel leaking from the trumpets.not a lot but it seems to lie in them.ihave set the floats to the correct levels.also at about 80mph the engine seems to starve of fuel othewise it runs superb.the car is aan elan +2s130 big valve running twin 40swebers.any suggestions would be very helpful thank you mike
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PostPost by: 1964 S1 » Tue May 11, 2004 3:53 am

Is the choke opening completely? It sounds to me like something is stuck. The 80mph problem may be a lack of air instead of gas. Does the car get driven frequently? What does the end of exhaust pipe look like? Be careful, leaking or too much gasoline anywhere can be catastrophic.
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PostPost by: worzel » Tue May 11, 2004 8:06 am

Re your fuel problem- basic areas to check are the needle valves (might be worn or there might be dirt preventing their full sealing, or might be that your fuel pump is too powerful and forcing fuel past the needle valves). Is only one carb affected- if so swap the covers around and see if the problem moves with them- if it does it's probably the valve.

As for fuel starvation at the speed it occurs pull out the choke and see if the problem disappears- this should confirm if it is actually weak- does the "weakness" occur at a steady 80 or does it only happen when strongly accelerating to that point- if it happens when accelerating then it does sound like starvation- but it might be caused by something like dirt in the fuel lines partially blocking the bore and then when you back off and the flow of petrol reduces the obstruction clears- have you recently run out of fuel and picked up dirt from the base of the tank/

Hope these ideas help.

John
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PostPost by: elanman3 » Tue May 11, 2004 1:23 pm

1964 S1 talks about fuel leaks being catastrophic, well I can vouch for that.
When trying to get my +2 to run after being laid up for 8 years I had a similar fuel leak through the carburettor trumpets (Dellorto?s). While turning the engine over the fumes ignited resulting in a small fire in the engine bay. Luckily I had a fire extinguisher close by and the only damage that I had was a few charred wires. After stripping the carb?s I found that one of the needle valves was seized open causing the float chamber to overflow. I quickly had them overhauled with new service kits by a professional.
If you don?t know enough about them (like me), take them to a professional. It?s better than looking at a pile of melted fibreglass.

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PostPost by: gjz30075 » Wed May 12, 2004 7:11 pm

If the carbs check out physically OK, then this might be a jetting/air corrector issue.
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