first thing to do is make sure that buzzing sound isn't actually the in-tank pump. They can buzz if the filter sock isn't situated right inside the take. There is an area at the bottom I've been told that the filter sits in to get the lowest area of the tank. If the sock is sideways then the pumps more noisy. First pump I installed is louder than the second one I did since I'd heard about the direction to place it.

Open up the fuel cap and listen to see if its the in-tank making the noise. Maybe even use a tube if needed. Or put your head under the car next to the main and see if its really making a loud sound. It could be that the tank is full of rust particles. I have a 245 that sat for years and I've gone through a few fuel filters cleaning the tank. I learned the hard way. I even switched the injectors after it got clean with some used ones. One filter had what looked to be really fine sand particles that settled in the ceramic bowl I used to empty the fuel into. It evaporates pretty quick or its also good for killing weeds in the cracks of the sidewalk.