ddezso

Thanks all and sorry for the duplicate post. I'm new here, posted in the engine section, then scrolled down and saw the carb section. My question was more logical there.

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

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

I hav noticed that one of the SU carbs on my 1970 240Z is low on the oil that goes in the top. Every book I have read says you MUST put SAE 20 oil in there. I can't find that at any local auto store. Is there an alternative or where would I find SAE20 oil? I also cant tell exactly where the fill line is. What is the proper level in the carb? Thanks........

No need for anything stronger than warm water, a wee bit of soap, a toothbrush, and some elbow grease........

I just got a 1970 240Z and could use some help mechanically getting it tuned up and checked out. I went to a couple of garages near my house and they told me that the 20 year old kids that work there have never seen a carburetor. Does anyone know of a good ZCar place in the Phoenix area? Thanks....