The LB50 fuel shutoff valve, a unit with carburetor. An alloy valve body with a lever arm and a click position, one flip turns the spool and cuts the fuel, no spring back; a brass nut locking the fuel line, fuel passing the spool before entering the float bowl; the valve bolted directly to the carburetor's square flange, four screws tightened diagonally, one less line, one less joint. For brush cutter and string trimmer small engines, replace the whole unit when the lever will not flip, fuel still enters when closed, the body seeps, the nut strips or the flange cracks, the spool and seal not sold separately. On fit, line up the flange holes, the lever direction and the inlet nut position on the new unit against the old one. Machines of the same type mostly fit, but fit is not guaranteed for every one; flip the lever twice to confirm the shutoff, then let the fuel back in and check the joints.

 FAQ 

Q1: What is this unit?

An LB50 fuel shutoff valve with carburetor, an alloy valve body bolted to the carburetor flange, with a lever arm and a brass inlet nut, fuel passing the valve before entering the float bowl, for small engines.

Q2: Is it the same as a tank petcock?

No. A petcock sits at the tank outlet and feeds by gravity. This valve bolts to the carburetor itself, so the fill point carries its own gate, one flip of the lever cuts the fuel without touching the tank side.

Q3: How do I check fit before ordering?

Compare the flange holes, the lever direction and the inlet nut position on the new unit with your old part. It is not guaranteed for every machine, so checking against the old unit is the safe way.