That filter just goes between the tank and the carb. I don't use them. I didn't catch what engine you are running. I have a couple OS engines that are doing what you are describing and it seems to be the needle valve leaking. I wish they would put them back in the carb where they belong. I am almost to the point of selling them and getting a different brand. A few more tests will tell. I took off my fueler and will see if maybe that is the problem. I am hoping it is. I have the same problem on 3 planes. What a pain.