Choke and Idle...

[ddezso]

I am the proud new owner of a 1970 240Z HLS3003137 but am not the most mechanical person yet (but working on it).

The car does not run too good yet and I think one issue is the carb tuning. I have 2 questions:

1) I changed spark plugs and the old ones were covered in black soot. When I start the car soot shoots out the tailpipe and you can barely detect that the exhaust is a bit black. Is this simply a too-rich fuel/air mixture or are there other possible issues?

2) I plan to get an airflow meter and tune the carbs. Before I do that I need to set the proper idle speed. My question is on the default position of the choke because that seems to be influencing my idle speed and mix. Currently, the choke is pressed all the way forward. If I pull it back at all, the idle speed plummets and the car dies. Should the choke be adjusted so it is in the middle of it's range, then the idle speed increased to compensate? I always thought the choke was there to increase idle speed at warm up, then be pulled back to normal speed to drive - but mine is all the way forward so it's of no value to me.

Thanks - I've got a lot to learn!

D

[Arne]

All the way forward is supposed to be the 'off' position. Pull back to activate the choke.

Yes, it sounds like your car is running way rich. Tuning your SUs is more involved than just using the gauge and synchronizing them. There are mixture settings as well. If you are not familiar with the workings of your SUs, get the video from ZTherapy and/or the Power Tune your SUs book before you start.

[26th-Z]

Let's dump this thread and go over the other one.