fuel draining from carb

[waynemags]

1980 720 bobcat. wisconsin vh4d. i had to put a fuel filter inline before the pump. prob now is after it sits for 20mins or so the fuel drains back to the tank. am i missing a check valve somewhere? any ideas? from the tank theres the fuel line to a clear filter then runs to pump. i had to install a primer bulb to aid in starting. should the fuel pump not selfprime when i turn it over?

 

[OldMachinist]

The fuel pump should keep the fuel from draining back to the tank. Did you just replace the filter or add it to the system?

 

[waynemags]

The fuel pump should keep the fuel from draining back to the tank. Did you just replace the filter or add it to the system?

added it. its just a clear plastic one. also had to add primer bulb. i thought pump might be faulty but was rebuilt with that engine. still have the one from my old engine. i didnt think it should let fuel back.