Okay, here is the situation. I currently operate a 250Z Gravely with an air-cooled 23 horse Kawasaki. I'm part-time, hoping to retire from my "day" job in 2-3 years, and use mowing income to supplement my pension, and, primarily, pay the health insurance bills. I bought my mower as a last year's leftover, and got a heck of a deal on it, three years ago. I have, however, kicked myself ever since that I didn't go ahead and buy a 60 inch deck, as most of my properties are larger, up to over 2 acres on a couple of them, and a 60 would help a great deal on productivity. So, I think, I'll run my mower for a few years, then buy a new mower before retirement, so I can get it paid for, and plan on using it for several years. I currently put about 200 hours a year on the mower, and hope to about double my business in retirement. By the end of this year, I'll have a bit over 700 hours on my Gravely, and have been seriously considering going ahead and purchasing a new one next spring. My reasons for considering this at that time are twofold, increase productivity, and get a mower back under warranty. Also, I think in my case, I might be better off not putting any more hours on my mower, because I'm pretty sure I can sell it to a friend of mine who is dying to have one for his personal use, but doesn't want to drop the bucks for a new mower. Mine is in excellent shape, and I think he'd be more likely to purchase it with fewer hours rather than after it has seen better days. Now, to the heart of this post. I have long figured to just go ahead and buy a Diesel. Lower fuel costs, more torque, longevity, etc. I was running this by my Gravely dealer the other day (I'm like 99% sure I'm buying another Gravely), and, if I understood him correctly, there is a whopping $2,600 difference between a Diesel and a liquid cooled gasoline engine!!!!!! I could swear that 3 years ago, the difference was more like $1,500, but I could be wrong. Anyhow, I don't see how I can justify the expense for the Diesel, even figuring saving 1/2 gallon of fuel per hour. I'd have to run the thing close to 2,000 hours just to make up the price difference, not considering any other additional expenses. So, I'm wondering what the rest of you think? Also, is there any real advantage to a liquid cooled gasoline engine as opposed to an air cooled one? In other words, if I elect to go gas instead of Diesel, is it worth the extra bucks to purchase a liquid cooled model? Gravely, for some unknown reason, doesn't currently offer an EFI model. If that should change before I purchase, then that might be the way to go. Anyway, any input you have would be appreciated. Thanks.