I was going to wait until it was 100%, but in the spirit of an update:
If there are *ANY* air leaks, and they aren't fixed, then you will be in an endless rabbit hole of trying to compensate via carb adjustments. Suspect points of connection are manifolds, Brake Booster elbows, and the Brake Booster itself -- just because it holds vacuum doesn't mean its not producing an air leak when you apply the brakes.
Even though I was starting off with a pair of super nice original one owner carbs, the years of use has taken a toll on them. You need to fully disassemble the carburetors, and verify that every mating surface is flat. The metal on these are super soft, and over tightening them will warp the mating surfaces
. Lining these up without gaskets you could see light passing through. We ended up having to remove a bit of material from most mating surfaces to get them within reasonable gasket range. Do not over tighten the carburetor screws!
Next, are you 100% that your float is within spec? It should be 12-14mm. Removing material from the carbs to get flush mating surfaces does not help this problem. I could not get my float into spec (currently at 14-14.5mm), which required cutting my own thick gasket which are about 2mm thick. I had the same issue as Ratwell wrote about on his dual carb page -- a 16-17mm float (with the popular Walker kit). I purchased a several aftermarket kits -- they're all crap. Start with the Walker.
The needle valves provided with the Walker kit don't help the situation either. The valve itself seats at a different height, and just replacing the valve with a correct NOS Solex valve increases the fuel in the bowl by 0.5-0.75mm. The washers that the Walker kit comes with is way too thick (1.5mm, and 1mm). I was able to get a 0.5mm washer from Tim @ Volkzbitz, and was able to find NOS Solex 1.2mm needle valve on E-Bay. Yes, they have the ball bearings, and I've heard the warnings. As Colin put it, don't abuse them and it will be fine.
If you're running your stock engine, you may be able to get away with the 14.5mm float.
The default combo from the walker rebuild kit doesn't come close to meeting float spec. The gaskets in the Walker kit are great quality but they are very thin. If you're float is not within spec, everything is going to seem like you're just one carb screw turn away from getting it right, and it will never happen.
Just because your idle jet solenoids are brand new and click does not mean they are functioning correctly.
Of course the inverse is true, if they don't click, they certainly are not working. If you are unable to get through Colin's tuning procedue because your engine wont run when you disconnect your central idle circuit without turning out the carb mixture screws out a ridiculous amount, it means one of the items above is not correct!
. Make sure you have no air leaks, and make sure your float is correct.
If you find yourself connecting and reconnecting the idle jet solenoids frequently trying to get through the procedure, and you notice that suddenly your engine is idling weird, pull your solenoids, blow some air through them, and try again. Sometimes just cycling the power to idle jet solenoids gives them the kick in the butt that may fix it.
As for where I'm at currently:
1) My timing is now about perfect thanks to the awesome and correct one year only 205J distributor (thanks Bill!). 28* max advance hoses off, 7.5*BTDC without retard, 11*ATDC hoses on. Previously I was getting a quite exceptional retard, and Bill has fixed that by adjusting the stop post.
2) My brake booster is still disconnected. I just haven't had time yet to get it repaired. While it held vacuum, when you applied the brake it it created an air leak. Apparently my brake booster is original and never worked since I owned it, and I just assumed that's how the bus stopped! Looking forward to getting that fixed.
3) My float is 14.5mm left, 14mm right. This is just enough out of spec, that with my 2L engine, I'm getting slightly lean accelerating (mid-high 14s), and the ever so slightest hesitation when its cold off idle hitting the transition ports. I'm jetted now 135 mains which seems to be the sweet spot for power and economy. I can get my float to 13.5mm by removing the needle valve washer, but with the hill I park on it floods out overnight. I still need to get another 1-2mm of fuel in the bowl -- I'm afraid to try bending the float tabs and braking them. The floats that come with aftermarket kits are garbage. The point of contact on the float arms which hit the needle valve are very close to the end where the metal post goes through -- there is actually a very small little notch/indentation on the original Solex float of where this point of contact in. Bending these is a recipe for disaster.
4) My fast idle on the chokes isn't working anymore -- it worked great when Colin was here, and presumably with the half dozen plus times I've taken these carbs off and put them back on, I've got the adjustment off. Working on this after I figure out the float.
As Satchmo stated in his thread, there is a huge
difference when these carbs are running right -- even if they are "close" it's nothing compared to when they are running right. The exhaust note at cruise is nothing short of amazing. Acceleration is smooth, and there is tons of power. The difference between my baby Weber setup and now literally is like driving an entirely different car. The power, slow speed drive-ability, and cold starts are game changers.
Lastly, there is no way I would ever have been able to do any of this without the VW community. Special thanks to Colin, Robbie, Aeromech, Telford, Bill, Tim @ Volkzbitz, Satchmo, and everyone else -- the VW community is truly a national treasure. I knew more or less nothing about this engine before starting with my first Airschooled and Itinerant appointments.
If you're considering booking time with Colin and haven't, you're doing yourself and your bus a major disservice by not booking time with them.