i have a 240z and this is my first carbed car. i and working on the engine and want to know if anyone can tell me how i can tune and adjust my carbs so when it is time to start up the Z the carbs are some what tuned. i have the duel su's.

I'm going through the same thing myself. I just got my Z started after the previous owner (my dad) had it in storage for several long years. It runs rough with lots of black smoke. A guy from the local Z club told me to take the carbs off and clean and adjust them. Anyway, from what I've read and been told, you need a flow meter to balance the two carbs. They cost about $30. I also purchased a video from Ztherapy (they're on line) that goes through how to adjust the carbs. The video also shows many other maintanace tasks. You may want to check it out. The video has a "home grown" feel but the price is right; about $15.

http://www.zcar.com/forums/read.php?f=1&i=300158&t=300155#reply_300158

i just got done with rebuilding mine using the video , it was great , still not up to speed with tuning but heh one out of two isn't bad

Starting with a new to you set of carbs should include a disassembly and clenaing before you do anything. These carbs develop wear and gunk related problems over the years that need to be over come or you'll very likely end up chasing your tail trying to get them to run when they never will.

The ZTherapy video and some of the books and write ups are excellent to follow and short of a couple of float bowl gaskets coming apart, disassembly isn't going to ruin much of anything.

I'd say get 'em apart, cleaned up and back on the car before you really try to dial 'em in. Remember the throttle shafts and bushings in these 30 something year old beautys are the achilles heel to this day. If they are leaking air, the choice then is to come up with some that aren't leaking air. Tinkering and tuning leaking carbs isn't going to solve much.....

I'd also suggest changing the fuel line from the float bowl to the nozzle if it's stiff, brittle or the big fat fuel line that can interfere with the choke linkage working properly. Also brittle line can break (can you say poof).......

Our JUST SUs certainly isn't hollywood quality but ol' Scott nailed 'er for content. There's about a ton and a half of info for $15 or $20 (2 tape version).

Bruce Palmer

sales@ztherapy.com

Salem OR

ZTherapy all the way; listen to Bruce, he the USA diety of SUs!!!!

SU's are certainly THE carburator to learn about tuning a carb, as they are about as basic as they come. Once you come to understand what is taking place with the fuel/air regulation in an SU, you will likely be able to understand a more complicated carb with idle, transition, and power circuits. It's just like learning to run...you have to learn to walk first! Good luck.