The fuel filter for the carb can just be snug tight with a wrench, you don't want to tighten it alot, it will damage the fittings. As for the 2 screws (bolts) for the item in your picture, (called a water neck or thermostat housing) I don't remember the exact torque but I think it's like 25 LBS, maybe even less, but you could do 20 or 25 and it would be fine. Pretty sure it's no more than 30, there's no requirement for that part to have any more than that much torque on it.