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Diesel Dilema?

Discussion in 'Lawn Mowing' started by MOturkey, Aug 10, 2006.

  1. MOturkey

    MOturkey LawnSite Silver Member
    Posts: 2,757

    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.
  2. Imow4u2

    Imow4u2 LawnSite Senior Member
    Posts: 377

    The problem I see with a diesel machine is the motor will more than out last the rest of the machine two fold.. I have a DC with 2000 hours on the 25 Kaw. It's not junk by any means but i was ready for a new machine after 4 years. That and if you mow any 1 acre or less properties the xtra weight is a problem in my area.....
  3. mike lane lawn care

    mike lane lawn care LawnSite Bronze Member
    Posts: 1,707

    diesel is the way to go if you need extra torqe, it will cut through the thickest stuff and ask for more, my grandfather who cuts 100 acres of lawn a week at one farm, swears by the kubota diesel that they have. he says the maintenence is less and the price is made up through engine longetivity, because there are verry little breakdowns. If i had the money i would buy a diesel, but the upfront cost is huge, so if you can afford it, by all means get the diesel.

    P.S. only 20 acres are done with the diesel ZTR, the rest is done with a 55 hp. diesel kubota tractor with an A/C cab.
  4. mowerman90

    mowerman90 LawnSite Bronze Member
    Posts: 1,491

    You could almost buy 2 25 hp replacement air cooled engines for the extra cost of the diesel. I own a Husler Super Z with a 60" deck and the 28EFI Kohler, the fuel savings are phenomenal over the 27hp Kohler I had in my last machine. Check out a Huster Super Z and demo it against the Gravely
  5. DEEJ

    DEEJ LawnSite Member
    Posts: 230

    You also have to look at the hours you put on a machine - not many at all. Even if you double the business you have now, you are not talking about many hours. The diesel would never pay for itself, in your case.

    There is the extra weight to consider, as someone else pointed out.

    As for liquid cooled on a mower, not for me. Air cooled has served me (and most of the industry until recent years) very well. There is no bulky rad and associated hoses, fans, and shrouds making the unit larger and heavier. Not to mention, these are all additional failure mechanisms (along with a water pump). Keep it simple works well for me in mowers. Air cooled all the way.

    Two of my units are Kohler EFI units (26hp and 28hp). I highly recommend them. The fuel savings are incredible, and the engines are smooth and very responsive, and are trouble free. Turn the key and go - no choke. I have an 18 Command carbureted on a 61" Ransomes Bobcat. It chews through the fuel at an alarming rate compared to the two 60" fuel injected units. The EFI units are way more horsepower and use way less fuel. Mind you I always thought the 61" deck was working the 18 pretty hard.

    For me, air cooled and EFI!!! I am a huge fan of diesel, but not for the hours you will be putting on.

  6. Idealtim

    Idealtim LawnSite Senior Member
    Posts: 939

    This guy has a point. The diesel would have to last 5000 hrs. plus for it to make sense.
  7. coyotekid

    coyotekid LawnSite Member
    Posts: 111

    I disagree that a diesel isn't for you.

    I also disagree, personally, that liquid-cooled is not the answer...but that's another debate I guess.

    A couple months ago I "penciled" out nearly the exact situation you're currently in.

    I currently run the Gravely 252Z as in my signature. With the 26HP liquid-cooled Kawasaki, it burns right at 1.6 gallons/hour.

    On the other hand, my Kubota 28HP diesel burns 0.9 gallons/hour working an 8" wider deck and double blades. And all claimed HP ratings aside, the 28HP diesel DOES in fact have much more "grunt."

    Remember that you can legally run red-dye diesel in the mower, so in my area that equates to roughly $0.50/gallon savings. Based on the better fuel economy and much lower fuel cost, the extra expense of the diesel up front is paid off if you run the machine 1000 hours.

    I'm really hoping the new generation of EFI gas engines will really increase fuel economy, but I'm still bent on diesels!
  8. SproulsLawnCare

    SproulsLawnCare LawnSite Senior Member
    from IN
    Posts: 365

    Why do you suppose they use diesel engines in semi trucks and farm tractors. Think about how many miles/hours that a truck driver puts on his rig every year.
  9. Shady Brook

    Shady Brook LawnSite Bronze Member
    from Indiana
    Posts: 1,517

    I can write off my gas tax just like off road diesel, so the tax savings are really not there. Diesel around me is about the same, or sometimes a bit higher then gas, so the savings is not there. How much more torque will a 25hp diesel have then a 27 Kohler, 28 efi, or other good size gas engine? I bet on paper nothing significant. I bet in the field having 2 more foot pounds will not put any more money in your pocket. We all like power, but at the end of the day a little more power is not going to help, even if you are planning on bush hogging.

    The diesel will save money on fuel. You do not put enough hours presently for that to justify going that route. It will save, but you would have to keep the machine for ages. Like others said, the rest of the machine will be needing some attention likely before the diesel goes down. They will come out with new fancy gadgets and decks that will make you wish you had the bigger and better mower before the diesel pays for it self.

    What if the engine goes down, is your dealer a good diesel mechanic? What happens if it goes down out of warranty, how much will it cost to repair? Bet a bunch more then a gas engine. What happens if there is a catastrophic that is your fault, or a workers that causes you to replace the engine? Ever price a replacement diesel engine? Scary.

    To me the biggest cost savings you will get with the diesel because of the low hours you use it would be the resale value. The diesel will bring more money for the machine when ever you are ready to part with it. This alone may cause you to break even with your purchase regardless of hours used.

    I don't think you will make a mistake by going either way, just some things to consider.

    WREBELMACHINE LawnSite Bronze Member
    Posts: 1,089

    I faced this problem a few years ago tried a diesel and have never gone back to gas. I do not how the gravely is because I have only seen one in my town where I mow which is funny because I am in Springfield which is only about thirty miles from bolivar. Anyhow diesel will give you much more power and definetly save you in fuel plus resale is much better! I have also found on my latest mowers that I have bought with the drought we have had that running the mowers at 3/4 throttle really saves on fuel! Good Luck!

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