New information, this may help someone else so I'll post it here.
Situation: 45 Dellorto DRLA leaks raw gasoline onto the throttle butterfly and chokes the engine. Only one throat does this, the other one stays dry. The leak is so bad that most of the float chamber will drain into the intake manifold, and the leak is big enough to hydrolock a 2 liter engine in less than a minute of standing still, whenever there is fuel in the bowl.
The shop I bought these from, as well as another carb specialist shop, both told me that while not very common, the DRLA line of carbs have been known to suffer from this problem occasionally. The culprit is a lead plug inside one passage near the bottom of the carb body.
There are several passages drilled all over the carb, and to be able to drill a certain passage, it was required to drill "helper" holes from another location at a different angle, that would intersect the main passage. Once these helper holes were drilled, and the actual passage finished, the helpers were blocked shut with a (soft) lead plug. The plug that blocks fuel from entering directly into the idle circuit, has broken loose on my carb and shifted. It's deep inside the carb, but it is accessible after you remove (drill out) another, bigger lead plug on the surface of the carb body. (near the accelerator pump and mixture screw).
WHY this happened remains a mystery, it's been known to happen to brand new carbs even. ONE reason could be excessive pressure.. from when one cleans the passages with compressed air. Sounds logical, the pressure could easily push a "wedge fitted" lead plug out. Gawd knows I've given it plenty of air *after* I discovered this problem :) SUGGESTION: when blowing carb orifices and passages clean with compressed air, do so from a distance so excess pressure has somewhere to escape. Do not push the air gun nozzle against the hole.
The shop agreed to replace the entire carb for me, or hook me up with someone who can fix it, of have it fixed for me. The other shop I used because of their carb knowledge, also gave me a name and phone number of a guy who has done this several times with success.
So, it's looking better now, I might be able to get the beast running before Friday after all.
Jan