If your Murray riding tractor has a hard time staying running you should check the fuel cap vent to see if it is clogged. If the fuel cap vent is clogged it will it will not allow air to flow into the gas tank, which in turn, decreases the pressure inside the gas tank and decreases the amount of gas to the engine. Clear any debris or blockage from the fuel cap vent.
You should also check the fuel cap seal to make sure it is securely in place and has not fallen off or fallen into the gas tank. If it is missing, replace it.
The model and serial number of your Murray riding tractor can be found under the seat or on the back of the riding mower.
NOTE: if you need a part for the small engine in your Murray lawn tractor, there will be a separate model/serial number for the engine. Here are the small engines that are available in your Murray tractor. Visit the page of the engine you have to find out where the model/serial number is located for your small engine model: