Sintered bronze.....I will try that! Thanks!! The gas gets cycled through pretty frequently so while I can't rule gum out ,this has happened going back to the early '90's for me. I have used Sunoco,Marathon ,Speedway-all the premium grade -sometimes with octane boost too and has still occured. I am pretty good about keeping things clean around the filler caps . I don't usually see debris in the seat so I put it back together and it will be fine for awhile then suddenly act up so that's what makes me wonder about different needle/ seat options
