We have a Craftsman LT100 that will start and go about 100 feet and then die. We are trying to figure out what is wrong so we can work to repair it. Any ideas on what could be wrong and how we could go about fixing it?

Have you checked the air and gas filter? I would start there then clen the carb. Good Luck

We have a Craftsman LT100 that will start and go about 100 feet and then die. We are trying to figure out what is wrong so we can work to repair it. Any ideas on what could be wrong and how we could go about fixing it?
Check to see if the carb is has a solenoid valve at the bottom of the bowl (should have wires coming out of it) Turn the key off then on (not to the starting point) with your fingers touching the valve if you don't feel a clicking then it may not beworking... The Valve 'cuts gas flow off' when its in off position as a safety feature... if its 'burnt out' then its not opening when the lawnmower is cranked thus cutting gas flow thus killing the engine.

Also check your gas for water bubbles it could be suckin good gas then when you move the mower thewater bubbles move and suck into and kill the engine.

Check You Safety Switch On Your Seat, I Worked On One The Other Day Doing The Same Thing And The Customer Was Well "very Heavy" And The Seat Engagement Tang Was Bent To Far Up, Re Bent Tang And Problem Fixed.
If You Know How Check To See That The Spark Plug Is Getting "fire" After It Dies, If Not You Have A Bad Coil.