Based on your problem description, most probably have a carb that need to be removed, dis-assembled and thoroughly cleaned before being re-assembled with a new carb kit and gaskets.
Engines that sit for a good while will have the gasoline to dry out inside the carb, leaving sludge/etc. in the small orifices blocking up fresh fuel flow - & will need cleaning out with a fine brass wire, compressed air and liquid carb cleaner.
Get the engine make/model/type info off the engine plate in your machine; go to the mfgr's website; download the available service/parts manuals along with the carbkit part number and do an overhaul. Work clean and keep close track of your progress with a camera to get the job done successfully. Good luck.

IF you had a safety switch issue you would have no spark and/or no crank, depending on which switch(es) were bad.
You have a fuel issue.
Probably a gummed up carb, but a clogged fuel filter or bad fuel pump (if equipped) could also be the cause.

EDIT:
In an extreme case, with very low temperatures, you could even have water frozen in the fuel line.
That's not very likely, since ethanol in the gas absorbs water.

This post was edited by bill_kapaun on Tue, Dec 31, 13 at 10:49

Carb clean as a whistle! Fuel lines clear. How can I check fuel pump?

Are the carb INTERNAL passages "clean as a whistle"?

Does the tractor have a fuel pump? Some do and some don't.
IF it does, disconnect the hose to the carb and crank the enine a couple times. It should push out a bit of gas.
How much did the new filter cost?

What's the Sears 917.xxxxxxx number of the tractor?
Some appear to have the Kohler Command and others the Courage engine. Others appear to have a Briggs.

Internal carb clean also.
Fuel pump is my prime suspect. 917.276900.

OP - if you already did following to carb on your tractor, you're cool on it. If only partially done, carb may still be blocked from supplying atomized fuel. Dried-out fuel gum is very hard to easily remove:
Remove carb, completely disassemble same. Soak in liquid carb cleaner to loosen deposits. Using a small dia. stiff brass wire AND a magnifying glass, probe/clean every orifice/passage in carb components. Use rattlecan carb cleaner and compressed air to blow out all orifices/passages, assuring all are fully clean.
Re-assemble carb using appropriate rebuild kit and new gaskets.

2) To check fuel pump, simply remove fuel line where it enters the carb body; hold line into catch container; remove spark plug wires; have assistant crank engine; should see good stream stream of raw fuel going into catch container.
If so, fuel pump, fuel filter are good. If little/no fuel flow, then replace each fuel line component (pump, line, filter, etc.) until good flow is obtained.

Unless you ground the disconnected plug wires, you are better off to leave them connected.
1. IF you are pumping raw gas out, you really don't want stray sparks in the vicinity.
2. The ignition coil(s)/armature still generate high voltage when cranking. IF the spark doesn't occur to a relatively easy ground path, it tries to go the path of least resistance. That means it "tries" to jump to the other internal coil windings. That breaks down the internal insulation in the coil. It's simply a bad practice.

I have 2 old spark plugs that I have shorted by bending the ground electrode into contact with the center electrode. When I need to ground disconnected spark plug leads, I insert these plugs into the plug boots and wrap a wet (with water) paper towel around the plugs and lay them on the engine sheet metal.
My aim with the with the dampened paper towel is that the moisture will effectively provide a broad path for the high tension spark energy to dissipate into while flowing back to engine ground and thereby never permitting an actual arc to occur.
The wet paper towel prevents any arcing that might occur if the plugs jostle a bit when cranking shakes the engine.

If it is easy to access the magneto kill wire circuit, I will simply connect an alligator clip jumper wire to the kill circuit conductors somewhere and ground the other end to the engine on a clean metal surface.

Thx for info. I have a closed system set up from used tubing from work and a plastic container. I will let u know how it does and results

Carb and gaskets it's rolling and running now!

good to hear and tnx for the feedback!