Any Kohler small engine guys out there?

Discussion in 'General Discussion' started by polishshooter, Oct 1, 2012.

  1. polishshooter

    polishshooter Active Member

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    My Craftsman 25 hp tractor is 8 years old...and this year it has started smoking pretty badly on start up and then smokes a little all the time mowing...

    About every time I mow lately it is below add on the stick, I fill up enough 30 weight to get it into mid range on the stick, I mow about an acre, and next time I have to add as much.

    I switched over to 40 weight last month, but it burns the same amount.

    Yesterday it started missing really badly, when I was mowing, so I pulled it back in to the garage...pulled the right hand plug wire...no change, put it back and pulled the left side...and it stalled.

    SOooo I know it dropped the right cylinder. I pull the plug, it is FOULED badly with oil. I clean it off, pull the OTHER plug and it is clean and normal, so I switch plugs and it fires up and runs normally, same amount of power, still smoking though, but I finish the whole lawn with no problems.


    Is my guess it needs rings, right or could it be something else? It is a pressurized oil system so could it be something else, like a cracked block?

    I hate to buy another tractor, but is it worth it to have this engine rebuilt? The GOOD news is I bought this one as "new" but as a "Returned Goods" item at a local Sears store at the end of the season in '02 so I bought it at about 1/3 the price of a new one at the time....



    But long ago my Dad told me to never buy a tractor with a Kohler, the only engine he ever had trouble with on his old Cub Cadets...was he right?
  2. sting75ray

    sting75ray Well-Known Member

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    Change the oil and add some Marvel Mystery oil back into it about 25% Marvel and 75% motor oil. If you have rings sticking this will break them free. Also keep some of the Marvel and dump it down the carb while on high idle. I had some of the engines on my pumping units that were using about 2 to 3 gallons of oil a week. After changing the oil and mixing it 1/3 and 2/3 and dumping a quart of Marvel down the carb they are running smooth and using no oil.
  3. Bindernut

    Bindernut Well-Known Member

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    Never done too much with Kohlers. Had a few of them in larger JD mowers but most of my side jobs these days are Briggs, Tecumseh, & Honda. I'm sure I'll start seeing a few of the chinese-knockoffs one of these days though too.

    Mostly likely it is bad rings on the fouled cylinder.
    It might be bad valve stem seals and/or worn valve guides.
    Could be a bad head gasket too, but that will usually push oil out the breathers and make a mess.

    I would start by de-carboning it first though. It might just have stuck rings instead of worn rings on the bad side.
    Get a can of SeaFoam and follow the instructions on the can to de-carbon the thing.
    Search YouTube for de-carboning vids too.
    Here's a link to de-carbon the old-fashioned way...using water & a high-detergent oil (ATF). http://www.ehow.com/how_5085773_clean-engine-very-old-school.html It's kinda tricky using water though...you can "hydro-lock" a small engine pretty easily and that will cause more damage. I'll recommend using SeaFoam

    I'm guessing it's a CV730 series?
    You should be able to find the full model-spec & serial #s on a sticker on the fan shroud...if it hasn't disappeared over the years. I can't remember if they also stamp it on the crankcase at all or not.

    You can do a complete short-block, but I'd recommend replacing the entire engine instead of a short-block if you're going that route. Might as well replace the whole thing if it's got that many hours on it...
    You're looking at pretty close to $2000 for complete engine that size though.
    A piston set will probably run $125-150 per hole and those larger Kohlers should have cast-iron cylinder liners so you can hone the bore.
  4. stumpjumper

    stumpjumper Member

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    +1 on the marvel oil. good gun oil also works well on circulating pump bearings. no smoke at high temp and speed
  5. Bindernut

    Bindernut Well-Known Member

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    Ahhh...you typed faster than me. Yup, you can use MMO to de-carbon an engine too. I've always had better luck with SeaFoam but either one will work.
  6. polishshooter

    polishshooter Active Member

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    Thanks Guys! I will try that. I remember using Marvel on an old truck I had...don't know if it worked but it was still running when I sold it, LOL.

    Yeah it's 8 years old, but it's not got THAT many hours on it to need a rebuild...never considered a stuck ring....

    And makes sense, if it was wear, BOTH cylinders would be messed up, right?
  7. Danwin22

    Danwin22 Member

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    I have a Craftsman tractor too, but with a Briggs & Stratton 19.5hp twin. Got it for $200 a few years ago and change the oil every 25 hours.

    It had a broken cable for the mower deck, frozen mandrels, a bad mower belt, bad starter gear and a few other problems when I got it but runs great now.

    We use it for mowing about 3 hours a week and a lot of barn chores like dragging the horse arena.

    These things are addictive.
    Last edited: Apr 22, 2013
  8. Bindernut

    Bindernut Well-Known Member

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    Yeah, if it's high-hours wear, it's usually pretty even on both sides...but not always.

    Another possibility besides stuck rings would be a broken ring on the one hole but that's not as common in small engines as with truck/tractor/car engines. Usually it's the carbon that causes problems with the little guys.

    Good luck!
  9. JUNKKING

    JUNKKING Active Member

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    Like the other guys mentioned sounds like stuck rings. Try the marvel in the oil or pull the plug and dump some seafoam into the cylinder head and let it soak a day or two. Once you go over a 20 hp those pistons are huge and get hot real quick. They gum up and the rings can stick. I dont know why they make a single piston engine so big. IMHO they should be two cylinders.
  10. sub-moa

    sub-moa Member

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    I guess it's all about what you have had good/bad luck with I personally like the Kolher products I would ,and have ,paid extra for a Kolher vs. a B&S However all have had some problems. I suspect they are all victims of cost competition. That said, The Kohler twins use a small rubber seal over the valve guides to control oil loss. I have seen these come loose from the guide and cause your symptoms. On the intake stroke when vacuum is created in the cylinder it can "suck" oil down between the valve stem and the guide. This will cause oil loss and smoke. I would suggest a compression test first if you have the capability to compare the two cylinders. If the compression is close to equal I would look closely at the stem seals. These can be replaced without an engine tear down using compressed air to hold the valves closed while the springs are removed. If you don’t have the expertise or tools to do these things then I guess you are at the mercy of the repair shop. Hope he’s honest. Good luck!
  11. JUNKKING

    JUNKKING Active Member

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    I just had a Kohler on a Husqvarna tractor do the same thing. I thought rings ... It was blowing pure black smoke! Just the little seal got sucked into the bottom of the valve. Kohler makes great engines, Onan is another engine that I like but getting rare. for the money B&S with a cast iron sleeve is the best for the money and probably the most easy to fix.
  12. polishshooter

    polishshooter Active Member

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    Yeah, Binder, it's a CV730S-013.

    One thing is that I pull the deck and put on a plow and chains for the winter, and usually plow with it at least a couple of times a month over the winter, normally. Sometimes much more than that, sometimes every day for a couple of weeks or so.

    However, last winter I bitched that I could have left the deck on, since it sat all winter in the garage with the battery tender on it, and was never once used to plow since we got virtually no snow.

    Now I wonder if it sitting unused and not run for like 3 months over the winter may have contributed to whatever happened, like a ring seizing? It started smoking and using oil when I started mowing with it this season.

    Up until the end of LAST season it didn't use a drop of oil between changes.
  13. polishshooter

    polishshooter Active Member

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    Hah, another clue!;)

    Junkking says his was pure BLACK smoke! Mine is very white smoke with a bluish tint just like starting up any old engine that needs rings...it gets less dense as it runs, but still white, but I'm definitely "fogging for 'skeeters" for a couple of minutes, and also whenever I throttle up or down....;)
  14. sub-moa

    sub-moa Member

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    Sounds like you are partial to this mower, I'd try to fix it. Take a good look at the valve seals first, it's easy and cost's nothing to look. Drop the hood off and remove valve cover on the suspect cylinder you can see if the seal is out of place thru the coils of the spring. Seals are about $8.00-$10.00 depending on where you buy them. Worth a try.
  15. polishshooter

    polishshooter Active Member

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    Thanks Sub, But I think I may try the MMO route first since I think the sitting for 3 months not being run over the winter may be the key...I just betcha that ring is closed up around that piston and isn't sealing....

    I bought a quart of MMO at Walmart tonight when I am out of town but got to thinking...

    ...what if after I drain the oil and replace it with the oil/Marvel Mystery mix, I pull the plug on the bad cylinder and use my Dad's old squirt oil can to squirt a bunch of Marvel into the cylinder first and let it sit a few days, then crank it over with the plug out to blow out any oil left above the piston, then put the plug in and try to run it?
  16. sting75ray

    sting75ray Well-Known Member

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    Putting the MMO in the cylinder and letting it set will not hurt anything. I had a boat motor once that was locked up and put some in each cylinder and let it set for 3 or 4 days. It broke loose and smoked like crazy for about 10 minutes or so.
  17. JUNKKING

    JUNKKING Active Member

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    What stingray said! Put it in there and let it set. I have heard of cylinder walls getting slippery and not letting the piston drag and combustion and compression went out the window but I have never seen it myself. I believe you need at least 75 lbs of compression for the engine to even fire 110 to 145 or so is probably the best you can get out of it. While you have it apart check and see if both valves are closing totally. It may need a valve job or just carbon removed around the valve or the valve guide may need honed a little.
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