1938 JD B Fuel shut offf

treeman53

Member
First off, fuel was pouring out of settling bowl, probably bad gasket. Three way valve was also stuck. Anyway, purchased new fuel settling bowl assembly, and new 3 way valve. Description of settling bowl says it does not shut of fuel, so what is the quarter turn petcock doing? I took it apart, and it seems the quarter turn would block fuel. Another thing, it only has the screen, then the gasket, then glass bowl. Wouldn't it need the screen sandwiched between two gaskets to seal? May be stupid questions, but I'm hoping this thing works with no leaks when I put it in...
 
The sediment bowl should only have one gasket and screen. Put it back just like it was and tighten with fingers and it should not leak. The quarter turn does cut off the fuel from the big tank only. The three way valve should be used to turn fuel on or off and gas in the small tank if that is how you are using. Most people just put gas in the big tank. Hope this helps
 
?[b:654c4848f0][i:654c4848f0]Description of settling bowl says it does not shut of fuel, so what is the quarter turn petcock doing?[/i:654c4848f0][/b:654c4848f0]?

Take a look at the [b:654c4848f0]FUEL SYSTEM[/b:654c4848f0] diagram below.

cvphoto21664.jpg


Note the Body and Shut-Off Valve (Key 37) part no. [b:654c4848f0]AC 1079 R[/b:654c4848f0] and Shut-Off Valve (Key 39).

Take a look at the photos below of the two positions of the shut-off valve.

cvphoto21665.jpg


cvphoto21666.jpg
.

Take another look at the [b:654c4848f0]FUEL SYSTEM[/b:654c4848f0] diagram below.

cvphoto21667.jpg


Note the Three-Way Cock (Key 11) and Fuel Filter (Key 19).

If the shut-off valve is CLOSED, then the fuel from the large tank does not flow to the fuel filter.

If the shut-off valve is OPEN, then the fuel from the large tank flows through the fuel filter to the three-way cock.

Take another look at the [b:654c4848f0]FUEL SYSTEM[/b:654c4848f0] diagram below.

cvphoto21674.jpg


Note the Gasoline Pipe (Key 9), Three-Way Cock (Key 11), Fuel Pipe (Key 17) and Fuel Control Rod (Key 22).

Take a look at the photos below.

cvphoto21676.jpg


Note that fuel from the small tank flows through the gasoline pipe (Key 9) directly to the three-way cock.

cvphoto21678.jpg


If the fuel control rod is in the [b:654c4848f0]O[/b:654c4848f0] Off position, then the fuel from both the fuel filter (large tank) and fuel from the gasoline pipe (small tank) does not flow through the three-way cock.

cvphoto21679.jpg


If the fuel control rod is in the [b:654c4848f0]G[/b:654c4848f0] Gas position, then the fuel from the small tank flows through the gasoline pipe to the three-way cock.

cvphoto21680.jpg


If the fuel control rod is in the [b:654c4848f0]F[/b:654c4848f0] Fuel position AND the shut-off valve is OPEN, then the fuel from the large tank flows through the fuel filter to the three-way cock.

Hope this helps.
 
The screen in your sediment bowl is smaller in diameter than the gasket and will not interfere with the seal, and cork gaskets WILL shrink. A new gasket will seal the gap between the glass and the metal valve body. You are correct in saying the quarter turn valve will not shut off the fuel. They don't completely seal. Your three way valve on the '38 is not controlled by a rod, but has a finger lever control on it, right? These may or may not completely shut off the fuel either. It's just a brass gate valve inside. If, over time, the carburetor fills, you may get gasoline flow into the intake manifold and the cylinders. Bad juju. The only surefire way to completely stop flow into the carb if this problem arises, is to install a brass needle valve in the fuel line to the carb. I know this is not original equipment, but it works.
 
www.greenpartsofva.com has a sediment bowl assembly that doesn't leak, and a positive shutoff assembly. A little spendy, but a great product.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top