new to carb's motors

[numbnuts240]

as the title says, my z is the first carb'd car i've ever touched. now i know that they're much simpler than fi cars, but when all you know is one thing, it's confusing at first to understand something different. i mean, seriously, how many of us can say that we would know our way around a rotary the first time?

that being said, i attempted to get my z home from my old man's place after finishing up all the brakes. apparently the starter is shot, so a few whacks later and he got it started. it idled like crap, but eventually smoothed out for the most part keeping steady around 1k rpms. every once in a while the idle shoots up to about 3k for a few seconds, then slowly settles down back to the 1k area. when i open the throttles it hesitates for a couple of seconds before the rpms will climb. getting off the throttle it drops in speed slowly, almost stalling, then settling back to the 1k idle. sometimes it'll stall. it's also backfiring through the intake.

now when we brought it to my father's house, it ran with zero problems, aside from only the passenger caliper providing any stopping power. an interesting drive, to say the least. i didn't touch anything under the hood except the bmc since we brought it home. i've done some poking around the web, as well as a text to greg, and read that it may be a dirty afm, out of tune carbs, timing may be off, or even bad gas. i figured i'd ask you guys for any ideas. it's getting closer to snow time here and my mother wants her garage back lol.

oh, and this is a 260z, all stock under the hood. yes, that means flat top su's

[evildky]

congrats on the z

there is no afm as you have carbs

you problem could be any number of issues, I'd start by opening up the float bowls, and makign sure the float levels are correct and that the needle valves are workign properly, make sure the bowl itself is clean and free of depris, often the floats deteriorate and clog the outlet holes at the bottom of the float bowl, make sure the fuel line form the bowl to the carb jet is clear and that the jets are adusted properly, check the oil level in each carb, atf is a popular substitute for su fluid

if you want the car to run well and be dependable, replace the stock carbs with earlier round top su's, less garbage on them to go wrong, if you insist on keepign the stockers I'd take the manifold off and send it to z therapythe 260 might still have points ignition in which case it's a good idea to check the points and gap before checking timing and inspecting the dashpot and vac lines for signs of leaking and finally checking ignition timing

hopefully some of this helps

[numbnuts240]

the flat tops will definitely get put on the curb with the rest of the trash. i just figured that if i'm going to get a handle on troubleshooting, i'd rather do it with the stock carbs in case i mess something up. i'll give your suggestions a shot after work. thanks.

[evildky]

it's much easier to troubleshoot the earlier carbs as they have fewer parts

[evildky]

and I forgot to mention, sometimes the throttle shaft bushings will fail allowing ait to get in around the throttle shaft, this could be your problem

[numbnuts240]

i'll add that to the list of things to check. thanks.

it's much easier to troubleshoot the earlier carbs as they have fewer parts

true, plus i can rid myself of all that useless and pesky emissions crap. thank goodness for the 25 year rule.