I have a 8 year old 200 hour plus LA 120. Other than the valves not adjusted properly in the factory, it has been trouble free since I got it. It even still has the original belts on it. Once a year I change the oil, grease all the stuff your supposed to grease, change the plugs and filter and never put it away wet or caked.
I have read on these forums others that have the same tractor as me and have had issues from day one. I don't know what makes two tractors so different from one another. I can only tell you about mine.
If I had found these forums before I got my tractor, I never would have purchased it because of all the horrible thing people say about the Box Store tractors and that would have been a big mistake.
The part you need seems cheap enough, I would just replace it and hope that that part was just a defective one.
Good Luck