Discussion Starter · #1 ·
My tractor seems to be overheating, and it has been suggested it is running lean. Before it began running rough, it simply started running fast after 30 minutes. Now it runs rough at lower speeds, and surges. Before it got worse, I had suspected a fuel line leak, and all lines have now been replaced. I got a vacuum tester, and the crankcase impulse line simply pulsates, with no net vacuum. I suspect this is normal. The fuel pump suction side pulls about 2.6 inHg. My vacuum tester pulls fuel freely through the fuel line, with no bubbles. Despite all that, my new fuel filter now fills no more than about 1/8", or barely a drop in the bottom. A year ago, it stayed about half full, and one day 3 months ago, it stayed nearly full. Now, I have no idea how any fuel has gotten into the carburetor at all. Apparently not enough has, though, because it runs pretty roughly, and surges. Why is it doing this? I tried using a shop vac to blow into the tank filler neck, and pressurize the fuel tank. With the engine running, the fuel filter still did not fill any higher. Tilting the filter to a near vertical while running should have purged the air, but it did nothing. I do not know what is wrong here. I suppose I need to check the fuel pump output pressure, too, but it looks like my vacuum tester does not test pressure. I can see how high it can pump up a piece of fuel line tubing. Let's see...3 psi is about 84" of gasoline height.