GXV 390 Fuel system

[Pac60]

I have fitted a new GXV 390 to a mower, it will start with the fuel tank above the carburetor but not if the fuel is below the carburetor. Is the carburetor gravity fed or a vacuum system ?

 

[ILENGINE]

Is the engine equipped with a fuel pump. Would be located between the fuel tank and the carb, most likely would have three lines. One for fuel inlet from the fuel tank, one fuel outlet to the carb, and a third coming out going to a someplace on the engine for vacuum pulse. But from your original description sounds like a gravity flow system.

 

[Pac60]

Is the engine equipped with a fuel pump. Would be located between the fuel tank and the carb, most likely would have three lines. One for fuel inlet from the fuel tank, one fuel outlet to the carb, and a third coming out going to a someplace on the engine for vacuum pulse. But from your original description sounds like a gravity flow system.

The engine came with no fuel tank & there isn't an electric fuel pump so sounds like a gravity fed system.
Thank you

 

[ILENGINE]

Pac60 the OEM fuel pump if equipped would of been a vacuum pulse type pump. But I suspect that it is gravity feed.