CaptainMajestic

Looks like that's the issue. Finally got around to taking another look and the rear carb has blue throughout the range, but the front runs rich at idle and blue on throttle. Not really sure why the two are behaving differently, but at least now it's drivable. Thanks!

I've got these kind of Air filters on, so no vent lines.

Should the vent lines on the floats be capped off or left open?

Update, I quintuple checked the float tab level is about 14+ mm from the lid. I also checked the fuel levels and they seem about the same. I also took off the suction chamber again thinking the jet needle might have been shifted back some, and it did a little so I went ahead and fixed it. Still having the same issue, the colortune mixture shows rich with the mixture screw all the way up, but I lose power under load. Thanks!

I've got two washers between 28 and 29 in that diagram.

I did some exhaust work a few months ago, and when I went to put the carbs back on I accidentally attached the fuel lines to the vent on the float bowls. My dumbassery compounded when I thought it was a good idea to blow compressed air in there and clear out the extra fuel. Definitely blew the float valve. as it was basically stuck closed and would occasionally rattle open. I could start the car, but it took a while to crank over, the front bank ran lean, and I would lose power on accelerating. Fast forward to the post rebuild, engine starts great again and the rear carb is still running bunsen blue on the colortune. I'm using this carb as the reference, and balancing the front one to match. I'm pretty new to the carb world, so I'm not sure what variables can contribute to lots of fuel at the jet. May be I assembled the mixture screw wrong? Are the two washers supposed to be closer to the bottom of the carb, or closer to the knob?

Thanks for the quick replies: I've been following the FSM and https://zcarguide.com/tuning-adjusting-datsun-240z-su-carburetors/ for tuning. At the moment, the float moves freely and the needle valve seems to be working correctly. I have the float set to ~10mm from the cover, and I double checked that the float actually floats in water. The carbs have been balanced with the engine running at about 750 RPM.

Hi everyone, I recently rebuilt my front round top carb because the float valve started acting funny. I double checked my float level and it does seem to be set correctly, but when I went to tune the carbs I could not get the AF mixture correct. I'm using a color tune, and even with the mixture screw all the way up the colortune shows flame orange. Any ideas why the carb is always running rich? Thanks!

Sorry for the late update, I let the whole thing sit for a day, mostly because I was busy with the holidays, and everything ran smooth and peachy! Thanks everyone for the quick replies

Aweswome, thanks! Just pulled the air filter assemblies and tried starting the car. It was hesitant to start, but got there with what seems like a weak idle with a light whistle coming from the carb air inlet that sounds a lot like a vacuum leak. Going to check tomorrow to see if this goes away with some extra air out. Another thing, after a bit of running I saw some wispy white smoke coming from the manifold gasket area for cylinder 1, and I'm guessing it's just some residue burning off, but again I'll check tomorrow and update you guys.

Hey everyone, I want to preface this with I am a total dumbass: Basically, I was in a hurry to reinstall my round top carbs on my L28 and accidentally connected the fuel lines to the upper vent instead of the fuel inlet and ran the fuel pump until fuel came out of the front air filters. I'm guessing all I need to do is let the thing air out for a day or so before running, but any advice/concerns are much appreciated. Thanks! -Michael

Yeah, sorry I meant the sediment filter that plugs into the electric fuel pump. Tank was cleaned and sealed.

Thanks everyone, turns out it was in fact a clogged fuel pump filter. I swapped it out with a new one and the problem disappeared. I need to figure out where the sediment is coming from as the fuel tank was recently restored and cleaned. Thanks! -Michael

Cool, does the wiring line up to the connectors on these? Or do I have to roll my own?

Side question, has anyone here run aftermarket transistor ignition units? I hear they are finicky at temp