Can someone tell me if these flat tops have an easy to access bone desolate screw? I just want to drain the bowl. 

Google images will help you, try it and see if you can find the drain. 

Damn! You've got my opening 24 hours of topics all about you and your car. 

Slow down. It's free advice, we're not charging by the hour.

Edited May 9, 2024May 9 by siteunseen

I have googled this for a long time.  No schematics on it. No photos or diagrams of where drain screw is.  Anyone know or have a photo??

thanks for advice

The law of gravity suggests that any opening on the bottom will drain the bowls.  Also known as chambers.

Look underneath.

https://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/carburetor-240z-(l24)/from-jul-72#1

It’s part #40,  good luck finding it…..

Better yet I want to take these flat top carbs off either to clean or to replace with round top. How in the world do you unbolt these bolts from the manifold the top ones are very easy. A couple of the bottom ones are easy but there are some bottom ones that are unreachable absolutely impossible to get here is there’s something I’m missing here. How do you get those bottom bolts undone on the bottom of these flat top carburetters can anyone tell me who has done this or knows how to do this?

Looks like I was wrong.  It's on the side.  Probably down by the bottom.  So it will work correctly.

After the old gas is drained, what next?

Nope. No drain screw, at least not on the set I had handy.

There was a heat shield on the bottom.

The shield covered this:

Still no signs of a drain screw, so I took off the bottom of the float bowl.

Nice and gunky!

Here's a side view of the floats.

And the float bowl chamber. No penetrations on the sides that I could see.

I'm thinking that valve is TOAST.

Anyway, when putting it back together, note that 1 screw is shorter than the rest.

The short screw goes where there is an indentation on the bottom cover.

Don't dismantle unless you have a new float bowl gasket on hand. And don't buy the cheapest kit since that kit does not have as many gaskets. (2 needed)

https://www.rockauto.com/en/catalog/nissan,1973,240z,2.4l+l6,1209170,fuel+&+air,carburetor+repair+kit,5964

Don't dismantle without the FSM!!

Only disassemble one at a time!

5 minutes ago, Patcon said:

Don't dismantle without the FSM!!

Only disassemble one at a time!

Oh come on, be brave!

Nope!!! 😉

You asked how to empty these carbs, you can get yourself a empty soap dispencer out the kitchen and unscrew the top and put the tube down the carb (or brakefluid container when refreshing the brakefluid for example) and the soapbottle is good to catch the oil out of your carb!

I also use this trick to clean out the powersteering tank (On other cars) , You replace this ATF partial every year and the fluid stays nice and clean as you always change a part of it.. and you don't brake any bolts or get leaks of changing the oil!  😉