Fuel Shut-off valve

[JohninKuranda]

I am just after clarification as to the thread size on the carb-mounted fuel shut-off valve (the thread marked in purple on the attachment). I am thinking that it is 1/2" - but wondering if it is UNF or NPT? Or is it another size?

Many thanks
John

 

[redmodelt]

1/2" (US) national fine straight thread.

 

[Daisyarney]

It’s most likely 1/2" NPT, since most carb-mounted fuel shut-off valves use tapered threads for sealing. However, to be sure, you could measure the thread diameter and pitch with a gauge or check the carb model’s spec sheet. Did you already check if it has a slight taper (NPT) or straight thread (UNF)?

 

[redmodelt]

It’s most likely 1/2" NPT, since most carb-mounted fuel shut-off valves use tapered threads for sealing. However, to be sure, you could measure the thread diameter and pitch with a gauge or check the carb model’s spec sheet. Did you already check if it has a slight taper (NPT) or straight thread (UNF)?

No it is a straight thread and uses packing to seal or in some cases a brass ferrule. The other end that fits into the carb is pipe thread.