Moeller Brass 1/4 In NPT Shut-Off Valve 033303-10
Moeller Brass 1/4 In NPT Shut-Off Valve 033303-10 — Product description
The Moeller 033303-10 is a solid brass shut-off valve with 1/4 inch female NPT threads on both ends. It gives you a simple, reliable way to isolate a fuel or fluid line at the helm, the tank, or anywhere you need to cut flow by hand. Straight-through brass body, no plastic to crack.
Sometimes you just need a clean way to shut a line off. The Moeller 033303-10 does exactly that. It's a brass shut-off valve with 1/4 inch female NPT threads on both ends, so it plumbs straight into a run of line without any adapters as long as your fittings are 1/4 inch NPT male.
We keep these on hand because they solve a real problem on a boat. Fuel line service, a primer bulb swap, winterizing, working on a gauge line, any time you want to stop flow without draining the whole system. Close the valve, do your work, open it back up. The brass body holds up to fuel and the damp, salty air in a bilge far better than a plastic valve will, and there's nothing in there to get brittle and crack after a few seasons.
The female-to-female port layout means both ends take a male fitting. That's the common setup for splicing a valve into an existing 1/4 inch NPT line. Thread it in with a little pipe sealant rated for fuel, snug it down, and you're done. No special tools, no proprietary connectors.
Who's this for? Anyone running a small fuel line, a fuel gauge sender line, a transfer line, or a low-pressure fluid line who wants a manual isolation point. It's a straight valve, so flow runs right through when it's open. Turn the handle to close. Simple as that.
A couple of honest notes. This is a manual shut-off, not a check valve, so it won't stop back-flow on its own. And it's sized for 1/4 inch NPT, so confirm your line and fittings match before you order. If your run is a different thread size, you'll want a different valve or a reducer.
Moeller has been building marine fuel system parts for a long time, and this valve is a good example of why boaters trust the brand for the small stuff. It's not flashy. It just works, and it keeps working. That's what you want out of a shut-off valve buried in a fuel line you'd rather not think about.
Key Features
- Solid brass body stands up to fuel and salt air, with no plastic to crack or go brittle
- 1/4 inch female NPT threads on both ends (female-to-female) for splicing into a standard 1/4 inch NPT line
- Straight-through design lets fluid flow freely when the valve is open
- Manual shut-off lets you isolate a fuel or fluid line for service without draining the system
- Sold as a single valve, Moeller part 033303-10
Why Buy from NVN Marine
- Authorized Moeller reseller, full manufacturer warranty
- NMEA member and ABYC certified, advice from real boat techs
- Same-day shipping before 3 PM ET on in-stock items
- NY headquarters and Fort Lauderdale flagship retail store
Technical specifications
| Title | Straight Angle; 1/4 Inch NPT Female; Brass; Single |
|---|---|
| Brand | Moeller |
| Manufacturer Part Number | 033303-10 |
| UPC | 739729333037 |
| Material | Brass |
| Valve Type | Shut-Off Valve |
| Thread Size | 1/4 Inch NPT |
| Thread Gender | Female |
| Port Configuration | Female to Female (F/F) |
| Sold As | Single |
Frequently asked questions
What size and type of threads does this valve have?
Both ends have 1/4 inch female NPT threads (female-to-female), so each side accepts a 1/4 inch NPT male fitting.
What is this shut-off valve made of?
It's brass, which holds up well to fuel and the damp, salty conditions in a boat's bilge. There's no plastic in the body to crack over time.
Is 1/4 NPT the same as 1/4 inch?
Not quite. NPT is a nominal pipe thread size, so the '1/4' refers to the pipe standard, not a literal 1/4 inch measurement across the threads. Match your fittings to 1/4 inch NPT and they'll thread together.
What is the thread angle of a 1/4 NPT thread?
NPT threads use a 60 degree thread angle with a slight taper, which is what lets them seal as you tighten them. Add a fuel-rated pipe sealant for a clean seal.
Can I use this valve to stop fuel flow while I service a line?
Yes. Close the valve and it isolates that section of line so you can work without draining the whole system, then open it back up when you're done. It's a manual shut-off, though, not a check valve, so it won't stop back-flow on its own.
Is this a single valve or a multi-pack?
It's sold as a single valve, Moeller part 033303-10.
