rossman

Never mind, a little more searching and I found the answer to my question.

I dug this brochure out of my step father's archive. I didn't see it posted anywhere on the site so I thought I'd share.

Try Benson's on Hwy 3 in Webster. They are real honest guys...but I doubt they will touch it either. If you take the head off the car then you'll have better luck finding a shop to remove the studs.

It turns out that the idle adjustment arm was bent such that it was contacting the aluminum stop before the butterfly valve was closing all the way. I bent it back straight, tuned and balanced the carbs now it runs great! Also it turns out the carbs were rebuilt by Ztherapy on 1-6-06.

Oh and thanks for the replies I think I'm going to take Walter's advice and get the Ztherapy video. Cheers, Ross

Am I right in thinking that the car should die if the throttle valves are completely shut? I think you may be on to something here. The ignition is a Crane Fireball XR700. I sprayed starter fluid all over all the gaskets, joints and hoses and didn't notice any rpm changes so I don't think there are any vacuum leaks.

Which one is the balance screw? The one just to the side by the throttle valve?

Actually they all look quite good, all six roughly the same light gray.

I recently purchased my '72 240z. The PO tells me the carbs were rebuilt by Ztherapy. They look nice and clean so I have no doubts. My problem is as follows. When I synchronize the carbs the idle kicks up to ~1200 rpm. The front idle screw is all the way out and the rear is in about 1 - 1.5 turns. On the front carb, with the idle screw all the way out (i.e. not cracking the throttle valve) I get about 9 kg/h flow using my Synchrometer. On the rear carb with the idle screw all the way out, I get about 3.5 - 4 kg/h. If I leave both screws all the way out, it runs but idles rough and performance suffers. With them synchronized the engine idles at about 1200 rpm but it runs really well on the road. I have verified that the linkage and center idle screw is not holding the throttle valves open. The timing is set to 12 degrees which I think is low, Haynes specifies 17 degrees IIRC. I have checked for vacuum leaks everywhere but I don't think that is the problem anyway. Any ideas? Thanks, Ross