CRAFTSMAN 917.370950 MOWING SPEED TOO FAST

I purchased the Craftsman 317.370950 walk behind mower two years ago and I HATE to use it, because it travels at much too fast a speed for my legs. This was an expensive purchase and, at the time, I thought I could adjust the walking speed because it has an adjustable engine speed. But, even at a slower engine speed, it still travels too fast. My old John Deere mower has a multi-speed transmission and I can adjust the walking speed and I love it but it is over 20 years old and near the end of its useful life.



Question: For the Craftsman 317.370950, has anyone here found a transmission kit, or an after market multi-speed transmission, that will allow a slower walking speed?



Or has anyone here had any success with replacing pulleys with a different size?