Riding Lawn mowers - John deere lawn tractor will not start

I have a 1986 John deere 212 lawn tractor with a Kohler engine (12hp) that will not start altho..

I have a 1986 John deere 212 lawn tractor with a Kohler engine (12hp) that will not start although it fires faster and faster but will not keep running. It acts as if starving for fuel. The fuel pump works. I cleaned all the passages in the carb with compressed air. The Problem still seems to be a lack of fuel. Ether does not help. What next.
Engine rebuilt 5 years ago.
model number K301AQS; the spec number: 47640

First thing to determine.
You're going to need an engine manual. Fortunately, if you go to http://www.asberry.net/Kohler.htm you can download one.
We know that an engine needs three things to run, compression, fuel and ignition and all at the proper time.
By using ether, you've effectively eliminated fuel as the problem. So first I would check for spark. Pull the spark plug, hook the plug wire back up and using insulated pliers, hold the metal part of the plug against the engine head while someone tries to start the engine. If there's a spark, then I would check the compression with a compression gauge. It's hard to determine the actual compression because of the compression release, but it will give you an idea.
Also, you can have ignition, but if it's not delivered at the right time, then the engine won't run. You'll need to determine which ignition system you have. You could have a points issue, a problem with the pushrod for the points, or for the electronic ignitions a flywheel that's moved out of position.
Check these things and let me know what you find and we'll go from there.