I worked on my lawn mower yesterday. My 3 year old girl told me that if I had any trouble fixing the lawn tractor that she would help me fix it.
If you recall, the the lawn mower slows way down when going up a hill. In fact, if I push the HST pedal all the way forward, the mower will come to a stop when going up a gentle slope. Per clemsonfor and ptgdigger's cues, I checked out the tension on the belt that drives the hydrostatic transmission pulley.
The idler pulley is located at the end of a swinging arm. A spring attached to the arm puts tension on the belt. I pushed on the idler pulley to see how much tension it was putting on the belt. After moving the arm the pulley is on, the arm did not return to its previous position. The arm that the pulley swings on did not freely swing as I thought it should.
I decided to remove the pulley arm, clean out the joint where it rotates on a pin, grease it, then re-attach it. The belt was showing wear so I decided to replace it.
In order to remove the belt, I had to remove the transmission pulley. There must be a better way but I eventually got the pulley off. I could not simply unscrew the 3 bolts holding the pulley in place because the pulley would rotate on me. So I removed two of the pulley bolts while keeping a wrench on the third bolt to keep the pulley from spinning. However, I still needed to remove the 3rd bolt. I tried wedging a large screwdriver against the pulley to keep it from spinning without success. I next broke loose the last bolt by putting another wrench on one of the previously loosened bolts. But I still had one tight bolt, but it wasn't as tight as when I started. Wedging the screwdriver against the pulley was enough resistance against the pulley to be able to loosen the last pulley bolt.
The idler pulley arm was held in place on the pin using a snap ring. You've all seen these things. They look like this:
We have all removed these things by cajoling them off with a pair of needle-nose pliers, screw driver, seance, etc. I figured it was time for be to finally go get the right tool. A trip to the hardware store 5 minutes away resulted in the purchase of a pair of snap ring pliers.
The snap ring pliers made removing the snap ring a simple task. Once I removed the snap ring, the idler pulley arm still did not want to slide off the pin. With much grunting, prying, and some help from my wife with a second set of hands, I was able to get the pulley arm off the pin. The pin and pulley arm joint were filled with gunk that kept the pulley arm from swinging freely. We cleaned the pin and pulley arm. I then greased and reattached the pulley arm. It now moved freely like it should. The spring that causes the pulley arm to put tension on the belt may be a little old but I hope is still strong enought to properly apply tension.
I'll get a new belt from Kubota and find out if I've fixed the lawn mower. I'm definitely not a mechanic but I actually got some satisfaction from working on the mower, especially when it might save me $3000+ that an equivalent new mower would cost.
Although I was on my back, working in a tight spot under the lawnmower most of the afternoon, it was almost fun. I have to say, being able to do this work in a garage made all the difference. Crawling around under the lawnmower outside on the ground or driveway would not have been much fun. Keep in mind, until we built this house, I've never lived in a house with a garage where I could do this work inside.