yes! harder to let fuel through. some filters it won't matter which way you put it in,others will be just like the ones for your car. they never show fuel flow direction[at least I haven't seen one] what I do is hook up some tubing at one end and blow through, then switch ends. how ever it comes out of which end the easiest is the way it should point to carb. And actually I do not run a fuel filter any more. First off there is one in my gas tank second if you start developing engine problems,like you think you have an air leak? Check fuel filter first always. Take it out of line and hook tubing direct see if problem solved.