As the title reads I cannot get my starting carb to quit leaking. Both carbs were rebuilt using all new stuff. The starting carb has the correct sealing washers but will not seal between it and the rail it attaches to. I've tried fiber and metal washers and even tried double stacking but still a leak. It did not leak prior to the rebuild. Any thoughts?

 

if new parts were installed as part of the rebuild, it's possible that they do not sit flush with the old ones and the gap exceeds what a pressure and washers can do. ...just a wild guess.

 

Where is it leaking? Blow up shown last. I had a similar issue & took part 41 from a spare set of carbs. No more leak. Sealing surfaces need to be pristine.

 

By the "Rail" are you referring to #16 "Fuel Passage" in the second drawn diagram with the big banjo bolt at the bottom?
There are two banjo bolts that hold the "Rail to the bottom of the AED and the bottom of the front Carb. Both can come loose and need tightening up without over tightening. (Brass in Aluminium thread) I have often had a small leak of fuel from one or other of these bolts and a quick cinch with a spanner normally does the trick.
If you have rebuilt the "Rail" yourself have you got the rail the correct way around. As I recall there is a large hole on one side and a smaller hole on the other side. I think the large side goes against the base of the carb but check you have this around the correct way. The "Rail" should go from the base of the carb at an upward angle to the AED as in the diagram and photo. Wrong way around and it sits at an angle and will leak. There are three fibre washers #42 that go one above and one below the metal plate #46 on the bottom of the AED and the third goes on the Banjo bolt #49 below the rail #48 as per the exploded photo diagram below.
If all of this is irrelevant as it has been done correctly then the only other suggestion I can make is to use some wet and dry paper to file the base of the AED flat along with the metal plate as you might have some distortion or dirt here which is not being taken up by the washers.

Exploded view

Diagram showing angle of rail


Photo showing angle of rail attached to the AED.

 

As I say above. The sealing surfaces need to be pristine. Echoed by Cass.

 

Yes. the leak seems to be at the banjo bolt and washers 42 and 43. I'll pull it apart once again and do some light sanding although the mating surfaces look good now.

 

Look for minor defects in the washers & Micro cracking in the Fuel Passage. 41 on my diagram. My problem from someone over tightening at some time in the history of the car. Showed up in ultrasonic crack detection. At the viscosity of petrol a very tiny crack will leak a lot. Fortunately I had a spare to make my alternative carb set whole. Cracked part went in the bin.

 

Many years ago, standard workshop practice was to soak the fibre washers in kerosene (paraffin) for 24 hours prior to use.
Apparently, this "conditioned" the washer for use.
Softening?
Another method of detecting cracks in metal is dye penetrant testing. Commonly used in aviation.
Cheers

 

Bill ~ with fibre washers that makes a lot of good sense ~ indeed softening the surface. The dye trick works well ~ very well. I was just lucky that I had access to a ridiculously over equipped workshop built by friends with deep pockets & every toy in the book. Every computerised gadget you could wish for plus the heavy stuff. They were even early adopters of printing parts. There was little that they could not do.

Both worked for Donaldson & where Donaldson where flapping about ROI ~ they charged their services to Donaldson. It ended up being a highly profitable business.