I was shocked to find this thread after trying searching for the answer to my issue.
I have the same exact mower (Toro LX420) that I purchased this year at Home Depot in June. I have had the same exact problem since I purchased it. It takes forever to start the mower. Being careful not to break the starter by holding the key too long, it turns and turns, let it sit for a while turns and turns, let it sit... turn turn turn... finally start. My problem just got worst. Because of all the starting my battery died. Bought a little 12v 6amp charger like the manual says and charged. Worked fine. and time after I go to start the mower and going through the turn turn turn process, I hear a pop. Right away I turn off the key and pull it out, but the tractor is still trying to start?!? I jumped to my sockets and removed the positive lead off the battery. The battery is now dead. I got a new battery and went to go connect it. As soon as I touch the neg lead(pos is connected) I see spark and tractor tried to start. I am lost now on what to do and probably going to pay big at the service shop, but before I do, anyone have any more advice on this issue?
I worked for Home Depot (selling lawn tractors etc.) a few years ago. One thing I remembered was they would take back something if the customer wasn't happy with it. You should go back to them and explain that you have had this problem since the machine was new. Ask them to replace it. If you push the issue you might get a replacement or at least get reimbursed for any money spent on repairing it for the starting problem. You need proof of the repair work.
Aside from that...here are a few things you can check. Remove the air filter and check to see that the choke (butterfly) is closing completely when you push the throttle lever to 'choke' If the machine has an automatic choke, it should be closed when the unit isn't running. You are putting it in 'choke' when trying to start it, right?
Have you checked for spark as explained in the thread above? It could be something as simple as an intermittent spark form the spark plug. If you're not sure how the check for spark, just try a different spark plug.
Check if you have a fuel filter on the machine (good time to change it). Also be sure the fuel is not contaminated with moisture or dirt. Best thing to do is drain all the gasoline from the tank and replace with fresh clean fuel. Dropping the fuel bowl and cleaning out the fuel from it is another thing to try.
'As soon as I touch the neg lead(pos is connected) I see spark and tractor tried to start.'
It's possible the started solenoid is stuck from constant cranking. These are inexpensive and easy to replace. Not sure if that's the problem but, it's possible.
Hope this helps...if not post again and I'll try and help some more!
That's my story...and I'm stickin' to it..
