I have a mahindra 4500 4wd, has 3 cylinder engine. It has always crank as soon as it turns with no problem until now. I was using it to spray fence line when all at once it puff black smoke. Now when you crank the engine it will turn and turn like it is trying to pick up fuel and puff black smoke. When it does start running the smoke clears up till you give it fuel and it smokes like you are lugging the engine. Drove it to the shop up a hill it has always climbed in high side 2nd gear, today i had to get in low 4th and it smoked real bad all way to top. I have change fuel filter, fuel lines, air filters and it is good clean fuel in tank. I could really use help with this, Thanks