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Is It True Exmark

Discussion in 'Lawn Mowing' started by puppypaws, Jun 19, 2007.

  1. puppypaws

    puppypaws LawnSite Fanatic
    Posts: 8,915

    I understand Exmark's engine rpm's are set at 3750 from the factory. Does the Kohler 28 efi consume oil on your Exmark at this rpm setting?

    The Kohler engineers say 3750 is their recommended high end setting and this will cause no problem with the engine.

    My 28 efi did not use oil but when I stepped the rpm's up from 3600 to 3750 there was a very noticeable difference in oil consumption immediately so I dropped back. I really like the 3750 it does better all the way around by holding the rpm's up but I don't know where the oil is going so fast.

    Any thoughts on this problem?
  2. bohiaa

    bohiaa LawnSite Fanatic
    Posts: 5,220

    :confused: :confused: :confused: :confused: :confused: :confused:
  3. tallimeca

    tallimeca LawnSite Bronze Member
    Posts: 1,229

    how you are adjusting your rpm's on an efi unit yourself.

    Go with the factory settings. The machines are run and tested at the factory settings.

    If you have any questions, contact the engine manufacturer for answeres. Exmark builds mowers, not engines. Exmark has the specs of what the engines are set up for. They build from there.
  4. hossmp

    hossmp LawnSite Member
    Posts: 100

    I am glad this topic came up. On saturday I was approached by a friend in the business that runs dixies. He was certain that the engines had been altered to run at higher RPM's by dixie. He was concearned with the longevity of the engines as a result. He was looking at the Ferris that I was running and wanted to give it a quick look. I never thought to check the rpm's on the motor before. I have the 26 l.c. kawasaki. I know the engine that is in question on the original post is rated at 28h.p. at 3600 rpms but not sure if they are then changed by the factory or not. I would love to know if some manufacturers are increasing the rpm's to get the blade tip speed as high as possible.
  5. puppypaws

    puppypaws LawnSite Fanatic
    Posts: 8,915

    I talked with a Kohler engineer this morning and actually read some of the post to him where people are talking about higher oil consumption at 3750.

    He said, this is the first I have heard of that problem and I told him maybe no one is talking with Kohler but I find it kind of hard to believe.

    Really intelligent human being for all practical purposes, he told me if the oil consumption went up at 3750 then turn it back and I said "duh" I realize this but your people state 3750 is that correct and he said yes.

    I told him Exmark came from the factory set at 3750 and that is what their literature states. I said Hustler says 3600 now who is right, Hustler that makes the mowers or Kohler who makes the engines. The response I got to that sounded like he could have something to do with the design of the space shuttle that blew up.

    I check the rpm's with a Protek 988 automotive engine analyzer which is very accurate so this setting procedure is not the problem.

    He ask me all kinds of stupid questions and basically what I told him was it never used any oil until I turned the rpm's up and then it used 8 oz. in 2 1/2 hours. I said there is no leaks and no smoking that I can see but I am moving so fast I could not see it anyway. I said it has to be going through the engine to lose that much that fast.

    If anyone else wants to tell them about this call: 920-459-1579 and use option 1.
    Come back and let us know what they tell you.
  6. fergman

    fergman LawnSite Senior Member
    from VA
    Posts: 286

    i have a 28efi on a 60 inch exmark ultracut i bought in 2004 an it used oil consistently and it was brand new and now 2500 hours its only a tiny bit worse. i just check it every morning. it has no leaks either.
  7. fearthedeere

    fearthedeere LawnSite Member
    Posts: 109

    I Have a similar Kohler Command 27 hp motor on my dixie chopper that is recommended to run at 3750 wide open without the blades engaged. As it's gotten older and more hours on it, I've found that it will burn a little oil, but nothing I can't live with. However, 8 oz. in 2.5 hours seems exorbitant.
  8. tallimeca

    tallimeca LawnSite Bronze Member
    Posts: 1,229

    RPM settings according to the factory technical manuals will also show you no load max rpm, and under load max rpm.

    I'm willing to bet if you run your engine wot with the blades off, you will see a higher rpm then with the blades engaged. 3750 has to be a no load number. Most of these 20hp + twins will run at 3600, under load.

    The internal governor is what keeps the rpms where they need to be under load. Linkage gets warn and out of adjustment from time to time.

    As far as OEM's increasing engine rpms to achieve blade tip speed, I highly doubt it for a couple reasons.

    1) I can run the same blade tip speed on a 28 efi kohler as I could on a 13hp tecumseh that came off an ariens snowblower. All about pulley drive ratio. Under load there would be a big difference...haha, but it is as simple as that. They measure max blade tip speed sitting there running. They don't measure max blade tip speed cutting grass a foot tall.

    2) The OEM's could have to manually run and adjusted engine rpm's on every machine they build. They don't do that. The engines are run and tested from the ENGINE factory. So if the RPM's were coming through incorrect, it would be from Kohler themselves. Imagine the cost if the Exmark, or Hustler, or Dixie factory sat there playing with Engine RPM's on EACH unit.

    8 oz in 2.5 hours seems like alot of oil. How old/how many hours on this engine? If it's brand new, it will consume oil for a while , at least 20 hours or so till the engine breaks in. I can't see 150 rpm's causing any excessive oil consumption problems. I would be looking at head gasket leaks into the lifter chamber. If it was using that much oil it has to be smoking.

    I will tell you from experience, Kohler engines do consume more oil then any other engine on the market in my opinion. I've seen it time after time. The Kohler Command 25's were BRUTAL. I've taken engines out of realitively new machines that are under warranty and have seen cylinders severely out of round, extreme ring gap, and almost no cross hatch in the cylinders.

    Kohler told me, and I quote "800 hours in a season is excessive use and they will not warranty it" Yes..........EXACTLY WHAT THEY TOLD ME. I said well what happened to your 1500 hours or 2 year warranty? They said it had to be dirt ingestion. I even offered to send them the block for inspection and they said no.
  9. puppypaws

    puppypaws LawnSite Fanatic
    Posts: 8,915

    The engine has 225 hrs. on it and did not use oil before I turned the rpm's up.
    I am saying you may put a half quart in during 50 hrs. I was really impressed with the engine and oil consumption. I had two 27's, one which used no oil to speak of and 1 that would use 1/2 qt. every 15 hrs.

    Kohler will tell you as they did me this morning that 1 oz. of oil usage every hour is normal to them, it darn sure doesn't seem normal to me.

    I have turned it back to 3700 at no load. I am going to see what this does and if need be I may drop 50 more. I will try to keep you posted.

    This is very interesting to hear the comments on this subject. I just hope enough people see this to give their personal experience with oil consumption and different rpm settings.
  10. fiveoboy01

    fiveoboy01 LawnSite Silver Member
    Posts: 2,988

    Well he's talking an EFI engine, it wouldn't have a mechanical governor, I don't think...

    I'd also be interested to know how you're changing the RPM, since we're talking efi, does a person have the ability to do it without hooking up to the ECU on these engines?

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