slow drip of gas off air cleaners on webers

[philbar73]

Hi all, the car seem to run well. It's not on the road so I just run it in the driveway on the weekends as I put it back together. It should be on the road in the next week or two and I don’t like gas leaks. I put new gaskets in the carb's and cleaned them as well as I could this past winter. The car has not been on the road for 29 years but the refresh is almost complete. They dripped a little from the intake the day I got the Webers brand new in 1978 but it never stopped me then. In my old age I do not want to drive it with any gas leak.

When I turn it off for the day I'm getting a slow drip of gas from the air filters. Can anyone help me locate and fix the problem? There is no drip when in use. I'm regulating pressure to 3 or 4 PSI. I put some paper towel under the carbs so I could see where it was coming from. It stops quickly when the carb's run out of gas. All three of them do it.

[Blue]

found this: http://www.lotuselan.net/forums/elan...rb-t14103.html

[philbar73]

Thanks Blue, this make sense. I will look and see if I can figure out where i can put in O rings or how i can seal the auxiliary venturis.

[philbar73]

I changed the fuel pump to a low pressure RX7 pump as suggested in many posts on this site. The gas dripping stopped when I turn the car off. I think the old electric fuel pump held pressure in the line when the car is turned off. The new pump must not hold the pressure or something but the dripping stopped.

[John Coffey]

Webers have trouble with fuel pressure over about 4psi. Its important to run a fuel pressure regulator.

[Lazeum]

Mine are leaking as well. I talked to many people with Weber (guys with Alpine A110 mainly & also Alfa Romeo's), they all have weber leaking... So I figure it is "normal" (even if I'd like them to be sealed tight also)

[Zedyone_kenobi]

I have a drop or two from mine as well. IF there is any gas left in the carb tube or venturi that leaks out into the flow path, it will find its way out of the carb unless the aux ventrui is sealed tight. The volume is so low I do not really worry about it. I just wipe out the drip tray/heat sheild out when I see some evaporated gas.

[philbar73]

Do your carbs drip when you turn it off or all the time? I had a 15lb pump and a regulator set to 4lb. They ran fine but dripped after i turned off the car. The only thing i can think of is there was presure in the fuel system after the pump was off and the fuel would seap past the flot valves over time causing the drip.
I will check to see if the presure drops when the power is off the RX7 pump and report back.

[philbar73]

As I suspected, the fuel pressure drops immediately when I turn off the RX7 pump. I guess it’s a centrifugal pump and has no check valve. I remember the old fuel pump and regulator held pressure for a few minutes after the pump was off. I am not using a regulator on the RX7 pump.
I disconnected the fuel line at the carburetor fuel rail and put the gauge directly into the fuel line. The pressure went up to 2.5 psi, I had the old fuel system set at 4 psi. I’m not sure if it’s the lower pressure or the quick pressure drop when the power goes off or both but whatever it is, I’m happy the gas dripping has stopped.
I also let the pump run for a while with the car off and no gas dripped, it makes me think the lower pressure makes a big difference.
I changed the pump because the old pump made a lot of noise.
Thanks to everyone that said the RX7 pump worked well and ran quiet. It turned out to be a good thing for me. It is quiet.
Maybe if I had lowered the pressure and set up the return line to the gas tank with the old pump so the pressure would drop quickly it would have helped.
Maybe you can quickly pull off the gas line as soon as you turn the car off to release the pressure to see if the carbs stop dripping. If it works I would be interested in knowing.

[philbar73]

Now that I have driven the car a few times, I still have a little bit of gas dripping. It is greatly improved.

[Blue]

What is the fuel level set to? 25.0mm from the top of the main jet well is optimal.