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L24 Engine Starting Hell... Help?

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Alright, so..

A few months back, I purchased me first 1973 240z with an unknown amount of miles on it from a younger Asian guy who had the car sitting in a garage for the last year. Prior to that, an older gentlemen had the car and did lots of work on the engine, body, and interior.

When I purchased the Z, it had next to no power so as soon as I got her back home I times the engine to 10-15 degrees and cleaned out/recalibrated the carbs. After that, pure power. It ran great for about a month until one morning I tried to start it and it just wouldn't run like normal.

To get it to start now, I have to choke it all the way and occasionally have to put starter fluid in the carb. When it does start, it revs high for a few seconds then comes back down and kills over. Since then, I've checked the engine pressure, rechecked the timing and carbs, the carb needle, the float and float needle, replaced the ignition and distributor with a Petronix system, checked fuel pressure and fuel lines, replaced the vacuum lines, took off the valve cover and checked to see if everything is in order.

I have no idea what to look for next, and have looked through every thread and manual I can find.

Any help would be greatly appreciated, as for im completely lost at this point.

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Thanks for the replies! 


Bad fuel?  It happens.


You forgot to mention your age and ethnicity/nationality.  


The night before the engine problems, I filled the tank with premium gas. The tank was about 25% full before hand. Do you think it's worth draining the tank? 



Check your starting circuits, you may have a jet tube stuck in the down position


I've only recently began learning about cars, where and what should I look for with the starting circuit? Does that have to do with the ignition system? I've replaced the distributor/coil with a Petronix electronic system. 

I've also taken apart most of the carburetor, including the jets that adjust the lean/rich mixture.



Could be a vacuum leak.


I've replaced the vacuum lines, because at one point there was a small leak. 



I'm going to continue working on the 240Z later today, and hopefully I'll figure something out. I've called a local mechanic whom knows a lot about Z's and he suggested re-checking engine pressure, as well as taking off the valve cover off and inspecting the works. Any more ideas would be greatly appreciated, I really do miss driving the Z....

Thanks a lot for the help!

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Reach up under the SU's and make sure that the jet tube is not pulled down...that's the starting circuit.


Your choke cables might be working properly, but if the jet tube is stuck then it won't return to normal when you take the choke off, and can make it run poorly or not at all, from being too rich.


You might have the opposite problem, your fuel pump and fuel lines might be clogged up, which sounds more like the problem, but the starting circuits are easy to check.


If you're still running the mechanical stock pump, and stock fuel rail (You should!) then check for clogs/stoppages.

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