I have a M5040, Runs great all good. after it warms up with pto engaged or running with no load or pto engaged. Motor bogs down and will die. Hard to get restarted but will start again if I let it sit a short time. Thought I should change fuel filter as there was no water in separator bowl. After change everything worked great. Installed new blades on the bush hog and mowed about 5 ac. and boom, she shut down. Could I have trash in the tank, as I sail no water in the separator. I am stumped and it is not over heating, seems to happen when I get down below 1/4 of a tank of diesel. Running green fuel, not red? Any ideas? Thanks in advance