Leaks

[Galwaylotus]

I'm getting my Weber-carbed S3 sorted and during tuning I've noticed that it is leaking fuel back through the inlet air stacks while idling. I should mention that the car isn't level in the drive. The right front corner is lowest. The carbs were rebuilt last winter and I've added electronic ignition and a Stealth BlackBox? controller. Float levels have been set according to Keith Franck's method, i.e. measuring the actual fuel level in the carb bowl rather than relying on the float-to-cover gap as described in the manuals. It seems to be running ok now (in neutral) except for the leaks. Anyone experience anything similar and is there a fix?

[prezoom]

Since you are following Keith's carb fix posts, you need to check to see just how tight your auxilular venturi's are against the carb body. Find some stiffer flat spring steel material to replace the weak "P" springs that push the venturi against the body, or cut a coil or two out of an appropriate sized coil spring. The DCOE 40 lacks the grub screw that the 45 has, and the venturi is thus a much looser fit in the carb body. It is important to have the verturi solidly agains the carb body where the fuel transfer port from to carb body to the venturi meet. Actually, the intelligent thing to do would be to drill and tap the carb body to replicate the 45 design.

Also, the trough in the carb body throat can also be a fuel passage back up the front of the carb. I found some Nitrile flat stock that I cut a strip from, that completely filled this trough out to the front face of the carb. I thought about using some "O" ring material, but I wanted a square piece of material that would completely fill the trough. I then added a small diameter "O" ring around the air horn where it inserts into the carb. Thus far, I have had no more fuel leaks from the carbs.

Rob Walker
26-4889

[Galwaylotus]

Thanks, Rob. Food for thought.

[Concrete-crusher]

Hi I had the same problem and found fitting a fuel pressure regulator valve cured it. I do have an electric su type fuel pump.

Hope that helps
Steve