My 2056 with twin Weber 40 IFD's developed a "vibration" between 2500 and 3000 rpms and several weeks ago I asked the world for assistance. I first thought maybe a loose pressure plate or loose CV, the consensus came back as a clogged idle circuit. Well, I took the carb tops off, cleaned the float bowls, blew out the idle jets at least 3 times and every time she ran great for a minute or two. During this adventure I added a 15 micron filter, pumped a couple of gallons of clean fuel, ..... It was driving me crazy. Yesterday I got lucky, when I opened up idle jet holder #3 I found what looks like a 3/8 long curly piece of fuel line??

Yes, thanks all contributors for the help and transitioning between the idle and main jets she was popping, spitting, backfiring and just running crappy. No longer, Got Lucky yesterday

Over my 71+ years I have found it's better to be lucky than good

I have nothing to do with the info you received, but I will say congratulations! Happy it worked out for you!

Persistence pays.
Results are the best reward.
I didn't offer advise with your issue but do know first hand how knowledgeable
and helpful this crew is.
Thank you for sharing.

That's good news

Isn't that what keeps us coming back for more? the quest of a sweet running teener