Engine was running super lean, have the nuts turned down six turns to far. I think it's a bit too lean yet but it runs, had to adjust the idle screws, rpms was too high. I'll install a small tach and play with mixtures next. If I remember there is an idle screw on each carburetor. Then there is a screw that adjusts just one for the purpose of synchronizing them.

The brakes have an issue, one of the brake reservoirs goes empty when I pump the brakes, got a leak somewhere, didn't see anything dripping on the floor. One problem at a time, engine first. Are master cylinder rebuild kits still available?

Jim

I wonder if the needles are set too low in the pistons? Closing off the fuel with the choke off

The needles are adjust correctly, one takes a straight edge along the piston to make sure the shoulder on the needles are correct.

There is a lot of history here, had a very difficult time getting the needles and floats adjusted right in the bloat bowls, that took an enormous amount of time.

I have a tach on the coil, next is to turn the nuts to go on the rich side, then rock back and forth to lean, looking for max rpms, at least thats what I understand.

I've been running fuel out of a 5 gallon gas can, the excess goes back into the main tank, ran my gas can out of fuel. The fuel tank is somewhat rusty, need to find if it is usable or now.

I discovered something I was doing wrong. On the bottom of each carb is a small button, the service manual calls it a "lifter." By pressing it with one's finger, can raise the piston slightly, I think the purpose is to make sure the piston isn't stuck. By pressing on the lifter, the piston goes up along with the needle. Logic says that would make the mixture more rich, so I thought and I would use that method to determine if my mixture was rich or lean, bad idea.

The manual says to turn the nuts 1/8 turn at a time to find the max rpms. I think I'm in the ball park, I need to find where I get the highest rpms by adjusting the nut on each carb. Once I get the mixture proper, I can return to setting the idle speed and the balance.

CO was very helpful in getting the floats adjusted, I ended up per his idea of adding weights to each float.

If I'm on the wrong track, please let me know, I'm open to suggestions.

Jim

Couple comments to hopefully help the process...

So I don't know exactly how you are handling the choke lever, but the typical process is to give it a good pull, crank the motor, and then as soon as it starts, push the choke lever forward "some, but not all the way off". It's not unusual to need partial choke for several minutes to keep the engine running smooth when cold. If you're pushing the choke all the way off immediately as soon as the engine starts, you are probably moving too fast. Give it some time to warm up with partial choke before you try to get the engine to run with no choke at all.

Engines don't like to run cold. and engines that have sit for decades are usually grumpy about being woke up from their sleep. It'll probably get better as you get more time running, but first bunch of minutes on an engine that hasn't run in a long time? Don't expect perfection.

Next is there's no way you should need to be running five turns down on a stock motor. If you're thinking you need five turns down, there's something wrong somewhere. I'm hoping that it's as simple as you need to leave the choke on partially for five minutes, but if the engine is warm and you need five turns.... There's something wrong.

And that "lifter" on the bottom of the carb does not make things richer on that carb, and in fact, it does the opposite. When you lift the piston like that, it completely disables the carb by making it super lean.

CO:

I feel pretty confident that the float levels are now correct. I have not checked for vacuum leaks, if the rubber diaphragm in the master vac was ruptured, that could be giving me a lean mixture and turning the nuts six turns down would compensate. Somehow I need to cut off the vacuum line to the mastervac. The engine used to have a carbon canister which I removed. I wonder if it had a vacuum line going to it, if so I wonder what I did about it.

I agree, years ago when the car was driven, had to pull the choke back to get it to start, then would back it off a bit to raise the idle speed until it warmed up, not the case right now.

I pulled the hose going to the master vac, sucking on it or blowing into it no obvious leak there. I did not try compressed air. This is a 260z with an automatic transmission. I see vacuum lines going to the master vac and down to the automatic transmission. There is another vac line from the front carb to the vac advance on the distributor.

There are two fuel rails, one from the fuel filter/fuel pump that feeds the two carbs, another one that feeds excess fuel back to the gas tank. The top hard line has nothing connected on either end, I think it was part of the smog system. I did find a hard line going somewhere, think it was a vent line to the gas tank, probably went on the charcoal filter cannister. The only thing that makes sense to me to have to turn the nuts so far down is a vac leak, but where? Would there be any point in connecting a vac gage to the intake manifold? I'm puzzled.

I haven't tried using a propane blow torch to leak propane around suspected leaks but it's not like this car has vacuum lines going all over the place, it doesn't. I'd attach photos but don't know what would help at this moment.

I think I would cap everything on the manifold that uses vacuum with an assortment of rubber caps. Then if you can get the engine started and sorted, add them back one at a time to check for vacuum leaks

I agree with Patcon. I'd cap off everything you don't really need right now, including the brake booster and the transmission.

And yes, I think a vacuum gauge could be helpful. You should be in the 17-20 inches of vacuum at idle. If you're at 10, there's a leak somewhere.

I also think pics could be helpful.