I have a 1987 DT 75, I have done everything that I think can be done to repair this problem, it will run great for a short while, seem like until it gets warm , then it will bog down and only run on (2) cylinders, let it sit for a short period and it' will do the same thing, have had carbs cleaned an redone, replaced fuel tank, all fuel filters, lines cleaned oil tank and repacled filter and oil changed fuel line connectors, don't know what to do, replaced diaphrams in fuel pump
