I burn offroad diesel in mine and have three or more tanks through this winter. (becasue I have a 6.0 ford but thats another problem all together) It does gel up when its cold I add some power service and that seems to fix it. Don't know how diesel could wreck it. just a very small hole in a piece of brass. Smell more yes. If you have a presure guage is it running enough high enough? Should say on the side how many psi. If your low check the hoses for cracks/leaks. Mine were dry rotted and leaking air. I switched them out with some fuel line I had laying around. Been good ever since.