Ray - I am a little concerned over my comment yesterday about the upgrade pump kits and nozzles. My experience with Prevosts is limited to the Webasto units installed by Prevost - these are 24 Volt units and are higher BTU output than are used in Aquahot units. The burner units are very similar and many parts are interchangeable - but I've been buying service parts from Prevost or at a truck repair facility familiar with the Webasto Vehicle heaters as common items. I have also worked on Aquahot and bought my parts for those Webasto burners from Aquahot (Vehicle Systems). The more I read about this problem the more concerned I get about what kind of a mix of parts you may be looking at. I suspect Jim is seeing the same issues. Just be sure the parts manual and the repair manual are both for the Webasto burner you have. Bottom line - if you have an 80,000 BTU unit you need the right parts for it. It is different than the 45,000 BTU units. My coach ('94 Liberty) has a DBW2020 Webasto in it (80,000 BTU). The .35 nozzles are for a DBW2010 (45,000 BTU). The fuel pumps are different part numbers however the "banjo fuel pipes, bolts, and washers appear to be the same part numbers. Mike's drawings and parts are correct for a DBW2020. My previous comments assumed that you were working on an Aquahot unit. I am not familiar with which system may be in your Marathon. It will take more research than I have done to determine how many parts are interchangeable but the nozzles, for one, are not.