I have a 2011 Hustler Super Duty (54" 26HP Kawa)-it has about 43 hours on it. I have noticed lately that when I am mowing and hit a fairly rough/bumpy piece of ground the engine sputters. It has never shut off and it only does this on bumpy ground-it sputters and spits but then it recovers and is fine. I thought it might be the safety switch under the seat, and I took it out and checked the plunger. I put tape over the plunger and mowed some more-the first time I hit a bump the mower sputtered. I have the standard warrant but I was hoping that someone might be able to give me some input.