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fuel consumption 25kawi vs 29DFI kawi vs 33 generac

Discussion in 'Lawn Mowing' started by supercuts, Jun 18, 2009.

  1. supercuts

    supercuts LawnSite Silver Member
    Messages: 2,806

    i have 3 mowers, a 25hp kawi, 29hp DFI kawi, and a 33hp generac.

    ive noticed the 25hp kawi is the worst on fuel. yesturday, we did a 12hr day, but i was only able to do 8hrs. so the 33generac and 29 DFI kawi did 12hr days, and the 25 kawi did less than 8. i also want to point out that the 29 DFI kawi and the 25 Kawi both went from small lawn to small lawn all day with a bit of drivetime. the 33hp generac had 2 stops running straight for 3hrs each ( no drive time = longer running time)

    i fill them full each morning. today the 25 kawi with 8 hrs of use used 5 gallons. the 29 DFI kawi with a 12 hr day used about 6 gallons and the 33hp generac with a 12 hr day with less drivetime used about 7 gallons.

    ive been trying to keep track as best as possible everyday and day after day the 25hp kawi seems the be the least efficent. its close, but id venture to say the 33hp generac may be slightly better than the 29hp digtal fuel injected kawi. so much for spending all the extra money on that engine. ive been very pleased with the 33hp generac engine. it DOES NOT NEED ANY MORE POWER. looking at another new bobcat i had the option betweenthe 33hp generac and the 37hp kawi. hands down im taking the generac.

    anyone else see the differences in engines? sorry, i dont figure the fuel per hour, simply my day to day differences
  2. Razorblades

    Razorblades LawnSite Bronze Member
    Messages: 1,151

    I may have missed it in your post but are all three mowers the same brand and model? Alot of people don't seem to understand that (as far a gas burner engines go) if your mowing accounts are the type that are working a 25 hp engine pretty hard, it will probably burn more gas than a 31-37 HP engine would, given the same size deck is being used on both mowers. It is a shame that the Generac engines have had the perception of being gas hogs and oil users that won't last as long as the other brands.
  3. kaferhaus

    kaferhaus LawnSite Bronze Member
    Messages: 1,444

    what size mowers are they on? If they're running the same "load" the smaller enigne will consume more fuel. Did you cut taller grass wtih the 25? Hills?
  4. Mike Blevins

    Mike Blevins LawnSite Bronze Member
    Messages: 1,390

    I had a 25 air cooled kaw on a 52 wildcat and now have the 61" 29 dfi on the Tiger. Bigger,heavier,mower with the Tiger and the 29 gets better fuel numbers than the Wildcat did with the 25 kaw. The 29 is exceptionally good on fuel in my book.
  5. Razorblades

    Razorblades LawnSite Bronze Member
    Messages: 1,151

    Yes, but you are using that special 10% kool aide blend, aren't you?:laugh:Just kidding. Seriously, what would you say that your avg. gph in normal to heavy cutting conditions is?
  6. Mike Blevins

    Mike Blevins LawnSite Bronze Member
    Messages: 1,390

    I havent got it down to a pefect exact number yet but I will try to get it when I start next week. I will fiil it up and mark the engine hours and start mowing my acccounts until I run out of fuel. Then I will do the math. Last time I checked it was around little less than 3/4 gallon per hour give or take.(When it was new) Now that its broke in good I will try to get an exact or closer number. I know the 25 couldn't touch these numbers. It was around .90 gallon a hour. Its hot today don't forget the KOOL-AID
  7. bpfaeh

    bpfaeh LawnSite Member
    Messages: 49

    I have the 29HP Kawasaki on my JD797 and once I got some loping issues taken care of I have been getting EXCELLENT fuel consumption. I dont have a "gph" number, but in comparing the amount of fuel I used with the 27HP Air cooled Kawasaki I have used, it is MUCH better. Worth the extra money....we have a Scag TT with the 29HP too and its the same as the JD. IMO, the fuel injection is worth every penny. I am comparing different machines on the SAME terrain....
  8. supercuts

    supercuts LawnSite Silver Member
    Messages: 2,806

    i didnt discuss brands or "work loads" on the engines, but.. the 33hp generac was being worked hard on the 2, 3hr each stops. the other mowers were worked hard on a few lawns but shared with quite a few easy (thin) lawns. all mowers have 61" decks, the 29hp DFI is on the scag TT and other 2 arfe on the bobcats
  9. greengiant9963

    greengiant9963 LawnSite Senior Member
    Messages: 762

    The scag turf tiger is shaft driven which will use slightly more power than the belt driven bobcat's.
  10. tacoma200

    tacoma200 LawnSite Fanatic
    Messages: 5,426

    Scag has tested the DFI/EFI engines against similar carburated at full load. I think during the test the DFI/EFI used about 25% less fuel. I think it was 1.6 gph DFI/DFI vs 2.2 gph carb engines. This was a test, not actual conditions. You should get better than that in actual everyday use because you don't run under a full load. My Kohler 27 got 1.29 gph and my Briggs gets between 1.30 and 1.5 gph. There are reports of 28 efi Kohlers using less than a gallon per hour. They are probably one of the most efficient. And of course all diesels get better than 1 gph.

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