Last weekend I got my Ford LGT 100 back to the place where I use it. This is the tractor that I had replaced the rings in because of oil burn. I put on the mower deck & started mowing all seemed to be working very good but after about an hour it started acting like it is running out of gas & died. I checked the fuel level, it is about a quarter of the tank full. It would start to run with full choke but not for very long & not enough power to move the tractor. I let it sit for about 15 to 20 minutes went back & it started back up. So I closed it back up & started mowing again. This time it ran good for about 45 minutes to an hour & did the same thing, acting like it was running out of gas & died. Again let it cool for 15 to 20 minutes & it would run for 45 minutes to an hour with the same problem. This is the closed side Ford GT on my LGT 145 the fuel line runs above the carburetor so thinking this may help I moved the fuel line on the LGT 100 but it did the same only running for 45 minutes to an hour. The LGT 145 is an open side Ford GT. This is one of the problems that this tractor was having before it started smoking from burning oil so it makes me wonder if this problem may helped to cause the oil burn. Both garden tractor are gravity fed with the gas tank mounted above the engine. I did a tune up on both tractors last spring with new points, cap, fuel filter, & air filter. On the LGT 100 I changed the valve on the bottom of the gas tank. I have replaced the old fuel cap & I know that Ford in the manuals states that if the fuel tank cap does not allow enough venting this can cause a problem but the problem still occurs with fuel cap unscrewed so I do not think that is causing the problem. I have plans to put a vent tube into the fuel tank. Doing some research I find that ethanol fuels can cause vapor lock easier as they get older but the same age gas is being used in both tractors with the LGT 145 having no problems with this but it is open sided. An after thought is maybe try using the tractor without that side on it. The tractor is far enough away that I do not have easy access but maybe able to have some else try this. Last year when I was having a problem very much like this I was thinking something with the coil because it would come loose in its mounting but I changed the mounting & have no problem now with it getting loose. I am looking for ideas on fixing this problem. One thought is a fuel pump but do not know if this is the right way to go.