ZS Carb rebuild; an unpleasant surprise

[Mike+2]

Hello to all,
I just received delivery of my +2 this week, which I was informed it was a runner. It was not. My first attempt to get it running revealed gas spewing all over exiting the carbs. I ordered two Zenith Stromberg rebuild kits.

After work today, I removed the carbs (first day above freezing for several days) only to discover that the secondary butterflies that route cold air over and and back were not present. The spindle, even more confusing was only an inch long and only on the external side. Presumably so it wouldn’t block air flow. But. What the heck? They must be there to seal the entrance of air, but would it?

So my question, knowing there are differing opinions on whether you should or not include those butterflies and crossover tubes, what do I do now?

I don’t have butterflies and spindles to add back in.

I don’t know if putting in the one inch spindles again will keep the air sealed.

In my shoes, how would you proceed?

[h20hamelan]

maybe it is a runner, with a bit of water etc in the floats-froze. Or maybe some odd movement when they were dry has them hung up or something. Is the float needle free? When did it run last...
could try gentle tapping with hardwood 1x1 or something light that won't damage anything if you have refit them and tried a second time. Is there a way to route the fuel away from any electrical source. Where was the fuel coming from exactly.
Is your space a bit warm? carbs like it above freezing or 32 in your case, more likely 40

[1owner69Elan]

Mike, you really don't want the secondary butterflies. But the crossover tube openings in the adapter plate need to be sealed. The adapter plate thereby functions as a balance tube between the carbs. Almost everybody that has a Federal Stromberg setup has done this. So nothing to worry about.

You get much better responsiveness without the secondary butterflies and crossover tubes. But any openings in the adapter plate need to be sealed including from perhaps removed spindles. When I had a Stromberg head, all I did was block the crossovers and turned the butterflies 90 degrees to the flow and locked in place. Never removed the spindles. Ran fine until I recently replaced the head with a Weber one.

[rdssdi]

as received from engine builder

[m750rider]

Exactly as stated above in the two replies. Eliminate the butterflies and the crossover tubes. Throttle response and performance will be much better.

[Mike+2]

Thank you all,

Carbs have been rebuilt. New plugs.

It appears all the work suggested above has already been done. There is a block off piece of metal on the intake manifold at the crossover tube. That’s good.

The secondary butterflies, the topic of this thread, were missing as well. As was the majority of the throttle shaft, leaving the outward end to block the external hole entering the carb.

I’m debating how to proceed with that.