mark 11/20/2012Three things required, fuel, fire, timing.
Let's just talk about fuel delivery which is a common failure on the the 240s.
Try staring it with a spray of starting fluid. If she starts and will stay running on short bursts of starting fluid, then that will narrow it down.
Behind the glove box you will find the white fuel pump relay. inspect, test, replace depending on the following:
Can you hear fuel pump running in the tank?
Can you hear the pump running located on frame rail near drivers side rear door?
Have you changed the fuel filter?
If none of that reveals the answer, test a spark plug wire for spark and pursue that type of problem.