I second the vote for needle/nozzle adjustment issue. Since you've already loosened the needles, suggest you CAREFULLY remove one and see how the piston action is. This should narrow things down quickly.

Also, another plug here for the late lamented Dime Quarterly, the last "newsletter" before everything went totally internet. Tons of good technical info, and the editor did several articles specific to SUs. All issues are available as pdf. If you can't access the site, let me know.

https://drive.google.com/file/d/0ByCvxnHNk90SZTVlNTU1N2YtZmQ2OS00ZjQwLWI1YTItMzlkZmIwNmZhZjJk/view?usp=sharing

https://drive.google.com/file/d/0ByCvxnHNk90SYWExMmM2YjMtMDNkMS00MDM0LTljZDQtNDU4ZGFlYjc5YjI2/view?usp=sharing

ISSUE INDEX -- https://drive.google.com/drive/u/0/folders/0ByCvxnHNk90SYzc4N2E1MWEtMzg0MC00YTE4LTkxZGQtM2RjODA5ODA1YjU1?hl=en

TOPIC INDEX -- https://drive.google.com/file/d/0ByCvxnHNk90SREtNSjQ2Wm9INzg/view?usp=sharing

This is what the choke cable looks like, similar to Z and Roadster styles but without the swedged cable ends shown. Nissan #18410-H2302 is NLA, but cables can be found on ebay, google and elsewhere as well as discussions for adapting other cables, like here:
https://groups.google.com/forum/#!searchin/bluebird510/choke$20cable|sort:date/bluebird510/DwdAB7Wvg8M/oRTXQHs1WXkJ

 

Edited December 21, 20177 yr by NVZEE

2 hours ago, 240260280 said:

Good Talking.

Attached is SSS carb manual excerpt.   Apparently there are plastic replacements for those brass floats.

You are the man! Went back down there and took the nozzle out and piston slides as it should. 19mm wrench to loose the nozzle holder. Put a philips down in the piston to hold it to the bottom. Thread the mixture nut all the way up. Center everything up and tighten the nozzle holder lock nut. Works like  champ now!!! Got a beer waiting on you in Atlanta!!!

1 hour ago, NVZEE said:

I second the vote for needle/nozzle adjustment issue. Since you've already loosened the needles, suggest you CAREFULLY remove one and see how the piston action is. This should narrow things down quickly.

You are correct and the links are great! I already put some possibilities in my watch list. May actually go with the TR6 choke cable because it's reasonably priced. As a side note where exactly is the choke cable supposed to mount?

If you're wondering about the handle end of the cable, it mounts on an L bracket to the right of the steering column:

 

Edited December 21, 20177 yr by NVZEE

9 hours ago, NVZEE said:

If you're wondering about the handle end of the cable, it mounts on an L bracket to the right of the steering column:

 

Will that interfere with the under dash AC vents? We have one we plan on installing.

Don't know about the AC. You could probably find enough flex in the choke cables to clear with the handle but the bracket might need modification.

9 hours ago, NVZEE said:

Don't know about the AC. You could probably find enough flex in the choke cables to clear with the handle but the bracket might need modification.

Thanks. I will work on it...

This is how they sit at the moment. Plated all the hardware and polished the overflow tubes. They will need some straightening. The buffer took them away from me  a couple of times.

Sourced the heat shield from Z therapy and a few other parts. I am still missing a few things. Throttle return springs and the hex head screws for the choke cable ends...

If I set the float heights, I think they would be ready to go on. Don't know if I have what I need for linkage...

@240260280

Blue,

I know you posted the float bowl needle dimensions for these carbs somewhere recently but I can't find it...

This doc?

HJL38W.pdf

56 minutes ago, 240260280 said:

This doc?

HJL38W.pdf

I don't know, does page 5 apply to sss type carbs? The floats in Cody's carbs are loose from the tab mechanism. We are trying to get his car running again...

Dual SU's are a distinguishing feature of the SSS model -- Super Sport Sedan -- so if you have 510 SU's they're SSS carbs.

But that isn't to say other SU variants aren't adapted. 510 owners are notoriously resourceful