I will share with you what I was told many years ago when I purchased my first scut or compact tractor. "This is not a agriculture tractor, sure it has a diesel motor but the injectors are smaller.
*We have had a problem with the dye used in "Home" or "Off Road" diesel in some of the small units." They recommended "Road Diesel" with two ounces of Power Service and four ounces of Marvels Mystery Oil per five gallons. I have always followed this routine and have never had a problem. Some use "Off Road" or "Home" Diesel and also have had no problems. (# 2 Off-Road - Home and Highway Diesel are the same except for the dye)
Now to the problem you posted about, it sounds like you have either a dirty filter, air leak in fuel line, air vent in fuel cap obstructed or a collapsed fuel line restricting fuel delivery. Time to start inspecting the fuel delivery system.