Gas tank vent

[Beckoning]

100hp oil injected, in line 4, 1988. Gas comes from a 18 gallon tank below the floor. What are the signs that the tank vent is clogged? If clogged, is there some sort of check valve in the vent line to keep water from the outside from going into the tank?

 

[jimn]

100hp oil injected, in line 4, 1988. Gas comes from a 18 gallon tank below the floor. What are the signs that the tank vent is clogged? If clogged, is there some sort of check valve in the vent line to keep water from the outside from going into the tank?

Run it- if it bogs and improves when the gas cap is removed, it's a good indicator, along with the sucking sound that accompanies loosening the cap.