No you don't have wimpy grass. With my shield installed I can let the mower sit and run over the same spot for as long as I want with no problem. Call the manufacturer they will probably have a shield for your mower. If your having the problem they probably now about it but won't fix it unless you complain.
NEgravely,
Your post caught my eye since I just purchased a Gravely Pro-Turn 152 XDZ a couple of weeks ago. It's my first ZTR and I looked at a LOT of high-end residential and low-end commercial ZTR's before deciding on the Gravely. Upon delivery, I noticed a few scratches on the motor shield on the back of the mower and the dealer ordered me a can of Gravely touch-up paint at no charge and the dealer has a good reputation locally(plus they accepted an offer of approx. $950 off MSRP) so I'm thinking they will address about any problem I have. I haven't noticed, though, the problem with burnt grass but I've only mowed twice thus far. I did stop several times and have not noticed any burnt spots in the grass(although there are "several" divets in the grass where I changed directions....these ZTR's take some getting used to and I'm getting better at making sure "both rear wheels are turning":0)
Anyway, I'm just wondering if your particular model may be having this prolem because of the size of the rear tires and how far your muffler is off the ground. In looking up the ZT 42 it appears you have 18 x 6.5-8 rear tires whereas my Pro-Turn 152 has 23 x 10.5-12 rear tires. That would make my muffler be several inches higher from ground level than yours. That's not to say that Gravely should know that and should have retro-fitted your mower with the shield if it needed it before you ever took delivery. Your dealer "did" get you the shield kit at no cost to you.....right??? I'm going to inspect my Gravely more closely, see if there is anything covering the bottom of the muffler(I haven't really looked or noticed), measure the distance from the ground to the muffler and keep my eye peeled for any signs of burnt spots in my yard. If I have the same problem, you can bet I will insist that my dealer make it right as I hope yours did. The heavy build and warranty coverages of these Gravely's put most of the other ZTR's I looked at to shame, so I can't imagine they wouldn't solve a minor problem like this.