I have a john deere la105 riding mower, about 1 year old.
It won't start. When I turn the key I get 1 click. I charged the battery and the same thing. I looked for a short or loose wire. I replaced the solenoid, same thing, turn the key and just one click. I replaced the battery, same thing. I can get it to start by directly jumping the starter with the battery, but that's the only way. It seems to me that the battery, the starter, and the solenoid are all good. I am stumped.

Ps... the only mobile john deere repair within 200 miles closed, so I have to rent a trailer and drive it an hour away! So much for my warranty.

I have a john deere la105 riding mower, about 1 year old.
It won't start. When I turn the key I get 1 click. I charged the battery and the same thing. I looked for a short or loose wire. I replaced the solenoid, same thing, turn the key and just one click. I replaced the battery, same thing. I can get it to start by directly jumping the starter with the battery, but that's the only way. It seems to me that the battery, the starter, and the solenoid are all good. I am stumped.

Read this Lawn Mower and Small Engine Repair I'd test the solenoid next. So far you can olnly say the starter works and likely the battery but you bypassed the solenoid which is suspect

Hi,
You say you replaced the solenoid. Try checking its ground. Otherwise I would next suspect the ignition switch, but I would definitely look to a ground problem. Could be loose engine mount bolts, also.
Peace,
Clarke

You might try turning the engine backwards to make sure the starter gear isn't stuck up.