11 hours ago, shoehorn_hands said:

I am not using points. When I bought the car, it had a Pertronix flamethrower already installed. I did replace the stock ignition coil with a Pertronix one and like it so far.

Good to know. That eliminates one of the extra variables. Don't forget to check the valve lash and timing, too. Those are important to have correct before futzing too much with the carburetors.

 It may be time for a new set of BP6ESs too. I've experienced a high RPM stumble that was cured by new plugs.

10 hours ago, Mark Maras said:

 It may be time for a new set of BP6ESs too. I've experienced a high RPM stumble that was cured by new plugs.

I swapped them when I started tuning the carbs. They’re gapped to 0.035 in. I figure since I’ve got the new ignition coil, they could take the max recommended gap. Does that reasoning hold?

Regarding the float levels, I think I’m going to mess around with them this weekend. Figure I’ll at least learn something if nothing else.

Thanks again for all the help. Everyone here’s been great!

.035 is the measurement that I always used. Good luck on the floats. Just for clarification, the float level doesn't have to be exact, just close. If you want it exact, the fuel level should be 3/8" below the carb bridge. That's 9 5/8 nozzle screw turns down from the top.

My 240z has the pertronix ignition and coil. I have started using the gap used in the -11 version of the ngk plugs...which is .039 - .043. 

I experienced what @Mark Maras mentioned above (high RPM stumble) about a month ago and swapping plugs cured it....even though the old plugs looked perfectly good.

I broke the golden rule though and changed two things...plugs and plug gap. So, I am not sure whether it was changing the gap or the new plugs that solved the problem. I suspect it was the new plugs.

Checking float bowl levels is a good thing to do at some point. There are many ways to do it. I do it the way Mark describes in an earlier post. FYI, it is a tedious process if you need to bend  the float tabs to adjust the levels. Can consume several hours...or several days depending on how quickly you get used to how it works.

Also, read up about ColorTune. Can be very helpful in getting the mixture right. But...getting the floats right is the first step. Think of it as your macro adjustment and the mixture screw as your micro adjustment. If your float levels are not in the ballpark then you can turn the mixture screw and have nothing happen at all.

J

 

I widened the gap too when I went to the ZX distributor and coil. Still the bp6es plugs though. Those newer ones with the needle looking core aren't worth a crap in my opinion. You want the most contact/strike area you can get.

Look for cracks or jump marks on your cap. They look like small lightning bolts to me. That means it's jumping spark from center to the cap points. Not good.