I have a 42 inch 19.5 horse craftsman mower that has seen its better days. key is bypassed to push button ignition switch. new battery and starter has new brushes and new top gear. the solenoid is bypassed. try to start and get clicking. sometimes starter will spin sometimes not. when the starter does spin it will only move the flywheel one turn at a time (if that far). battery is fully charged use a trickle charger.

SOURCE: Craftsman riding mower loose belts need tighting

http://www.disruptit.com/manuals/L0403195.pdf

Here ya go.

SOURCE: Craftsman 42 inch riding mower. Runs great

how old is your plug? try cleaning and regapping it or replacing it at any rate make sure it is gapped correctly also make sure there is no rust dust or debris is on flywheel or coil also the flywheel keyway does more than hold the flywheel in place it servs as a timing pin and sometimes the slightest wear on it can cause the machine to start hard but otherwise run great good luck hope you find the problem.

SOURCE: Craftsman 17.5 HP 42 in mower stops after approx 1/2 hour of use

Hello jon3208:

>>The Following is a Basic Instruction File I made for this. Any Input is Appreciated. I Usually Suggest you Check the Following in this Order for a Problem like yours. **CHANGE ANY SPRING STYLE HOSE CLAMPS TO THE SCREW STYLE HOSE CLAMPS*** 1- Check the Gas Tank Cap and Ensure it is Venting the Tank. A Vacuum Builds in the Tank and the Gas Flow Stops or Slows (15 to 45 Minutes and if the Small Grainular Sand is in the Tank it can Take Several Days of Constant Running to Bring All the Sand Particales to the Tank Outlet Port) to a Point it Shuts Off the Engine. 2- Operate the Equipment Until it Quits (15min to 1hr). Then Immediately Check for Fire from the Plug. If the Plug is Firing, then 3- Check the Carburetor Solenoid. If the Carburetor Shut Off Solenoid has Current, then Remove the Carburetor Solenoid and Go to the Hardware Store. Purchase a Bolt of the Same Diameter and Threads. It Needs to be 3/4" Long. Put this Bolt in Place of the Solenoid. If this Corrects the Engine Problem, then Replace the Solenoid. ***NOTE: THIS IS FOR CHECKING THE SOLENOID ONLY I NEVER SUGGEST YOU OPERATE THE ENGINE WITH THE SOLENOID OUT OF THE CARBURETOR EXCEPT FOR TESTING PURPOSES*** Sometimes the Plunger is Moving, Just Not Far Enough to Allow the Gas to Enter the Jets. 4- Depending on the Model Mower, it can Also be the Pickup Tube in the Gas Tank. If No Fire, then Remove the Shut Off Wire from the Coil and Check for Fire. If Still No Fire, then the Ign Module or Coil is Bad. **Even if the Coil is New of Fairly New, it can Still be Bad.** On JD Mowers; Remove the Igniter/Module and the Coil and have the Local JD Dealer Test them.
Please, Do Not Hesitate, If I Missed Something or you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance.
Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Be Happy. Thanks.

Good Luck

Respectfully

jbridger (John)

SOURCE: craftsman 42 inch deck won't run

Check proper belt routing. These models are a little tricky. Also check tensioner spring.

SOURCE: need a manual for a LT1000 craftsman 19 1/2 HP 42 inch mower deck

You can download a free copy at www.managemyhome.com or you can go to www.searspartsdirect.com and buy a copy along with look at the diagram that you need.
Good luck!