Sounds like the fuel pump. Does the fuel filter ever fill up? If not the pump is most likely the culprit.
We have had quite a problem with dirt dobbers around our place this year, so it is possible it is the vent. It should be toward the back, somewhere it won't get a lot of water splashing on it, but on the outside of the hull, not in the cockpit or topside. You should be able to smell it out.