Would you check a couple of things for me. You have what is called a pulsating-jet side draft carb. You said that you installed a new diaphragm. Did you make sure that the spring and spring cap were install correctly. This order, spring, spring cap, diaphragm, cover. If done right this diaphragm draws fuel up the long pickup tube from the main tank into the small resiviour tank. Second, pull the tank and carb and see if there is fuel in the small tank. I know this is a pain to do. If there is no fuel, then the diaphragm pump is not working properly and then we look at why.