I've been having some problems with my 122 wagon and wanted to get it
running better before I get into engine swapping with my other 122 wagon.
I suspected carb problems so I decided to install one of 2 pairs of HIF6
carbs I have been keeping for such an occasion. I'm using the standard
B18 aluminum manifold but it has been opened up so that the carb flanges
have a 2" hole (for HD8 carbs) rather than the original 1 3/4" hole.

First thing I found out was that the front carb would only open a little bit
before some of the linkage hit the sheet metal heat shield. The cast iron
manifold is built differently, as is the B30 manifold so this was an unexpected
problem. I clamped another manifold in the vise, bolted the heat shield to it
with all 8 nuts and big washers and went to work with a hammer and a round-end
punch until there was enough room for the rear-facing arm on the carb to go
through its full swing to wide open. This warped the shield a bit and made
a slight rip in it next to the front carb but I think it will work OK.

I bolted the carbs on, hooked them up and started the engine. Idled at about
2500 rpm and mixtures were WAY unbalanced. I took the carbs off and took
them apart and found that one of the jet mounting plugs was not screwed in
and that both throttle butterflies were loose. I fixed that and checked to
make sure the float valves were tight, along with everything else and put it
back together. Idle came down to about 2000 rpm, still much too fast.

I figured it would be a good idea to replace the throttle shaft seals and
I also needed the actuating arms and one return spring for the other pair
of carbs so I called Joe Curto at College Point, New York. While doing this
I thought about the little flapper valves in the throttle butterflies, and
mentioned them to him as a possible cause of the fast idle. He said, "Oh yeah!
You gotta solder them shut!" So I went back out and soldered them shut. Worked
pretty good. I still have a mixture unbalance and somewhat unstable idle,
but it is now driveable. I believe that with continuing work in the coming
days I can comb it out fairly straight.

I'll keep you posted. Meanwhile, if you change to carbs that have an overrun
valve in the throttle butterfly and you can't get a reasonable idling speed,
maybe you oughta try soldering it shut. If you have enough engine vacuum,
it is just like opening the throttle about 1/6 of the way or so.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma