I also posted this exact same thing in the FAQ forum. But, there have been a couple recent posts on the Late Model board here where this info might be useful. So, now you can see these nice pics in two places!

Or, what is *supposed* to be in a JD350 fuel tank! More often than not, this stuff is missing. I got lucky when I bought my 78 JD350C from Mark a couple years ago. This stuff was actually still in place. Actually, everything was still in place and the machine not all beat up.

So, the first thing is the vent tube at the bottom of the tank. There are always posts about machines that run at first and then die out. This tube is a vent that passes from the bottom all the way to the filler opening just under the cap. This lets air into the tank to replace the fuel as it is drawn out. Well, when it isn't plugged up, anyway. This is looking at the bottom of the tank from the rear of the machine.

All the other shots are from kneeling on the seat looking back at the tank.
Next, we move up top to the cap. Notice the nice rubber gasket. This, so fuel doesn't slop out up by you. Often missing to vent the tank because the vent tube is plugged....

Next, we have several parts. A dipstick, a retaining ring and a filler screen. You can see the vent tube.

This is the dipstick. Passes thru the hole that isn't the vent. The bigger one that is actually part of the filler screen. So, if the filler screen is missing, you won't have the second hole. Let's you check fuel level.

Here is a better look at the upper vent tube. The shiny one, not the black one. It is easier to pass a cleaning wire from the top down to the bottom.

This is the ring that holds the screen in place.

This is the fuel fill screen to catch some junk before it gets in there to begin with. You can see where the dipstick goes alongside the screen.

This is the filler opening missing all the parts. All you see is the upper vent tube.

Hope all that helps!
Stan