My 116H project is coming along, New muffler and new tires. My problem right now is keeping it running. It starts just as it should then dies after 10-15 seconds. There is fuel at the filter, so I guess one of the pumps is working, the one under the battery is new. The carb has a 3-screw pump. This 2 pump setup has me stumped. If the carb mounted pump fails shouldn't the external pump be able to push the gas on thru, or is that my problem?