Engine Smoking

Discussion in 'Mechanic and Repair' started by mezammit, Apr 27, 2008.

  1. mezammit

    mezammit LawnSite Member
    Posts: 94

    I have a 2006 Lazer Z Hp with a 27hp Kohler engine on it. I bought the mower off a guy last year the mower only had 75 hours on it. I changed all the fluids at the end of the season last year and now the engine is smoking. When I first start the engine up it will bellow out white smoke then go away I figured this is just condensation. After the engine is warmed up it will smoke a little black smoke not muck though. If I pulse the throttle up and down it will also smoke a little black smoke. When I changed the oil I put Mobil-1 10W30 synthetic in it. I am wondering if it is the synthetic oil that is causing it to smoke. The mower now has 127 hours on it.
     
  2. action13

    action13 LawnSite Member
    Posts: 29

    Black smoke signals rich mixture. White is usually moisture, but could also be a bit of oil too. I wouldn't run a synthetic oil, I would only run what is recommended by the manufacturer. I would also after warming the engine well resetting the main mixture screw (high speed setting), but would also check the idle mixture too. Check the spark plug, it tells a million stories. Black means it is running too rich. Keep in mind with small engines, if you increase or decrease the throttle too fast at times it will puff a little black as it needs a split second to use the gas thats in the chamber. They don't react as quick as a auto engine to fuel changes. ......Check the obvious too, is the choke partially closed? I doubt it or it should puff black smoke all the time. Sounds to me as if the throttle is being closed or open a bit too fast not giving time for the engine to adjust to the fuel changes. When it does, the puff stops.....Hope this helps a bit.......Tom The Mower Shop.
     
  3. mezammit

    mezammit LawnSite Member
    Posts: 94

    Thanks for the reply yeah I was pulsing the throttle fast so that does contribute to the smoke. I think I am going to drain the synthetic and just run a regular 10w30. The dealer told me that synthetic would be all right to run but hey the dealer will tell you anything to get your business. I know that the synthetic is a lot thinner than regular oil. Would changing the oil from synthetic to regular cause any damage. I have heard once you run synthetic that is all you should run but what about the other way around synthetic to regular oil.
    Thanks for all the help.
    Mike
     
  4. action13

    action13 LawnSite Member
    Posts: 29

    No it's fine, you can change right back to the regular oil, make sure the manufacturer calls for 10w-30, and not straight 30. This time of the year most recommend straight 30w. Usually they use the 10w-30 in snow blowers because of the colder temps. The oil then begins at 10w to give easier starting, and quick start up protection. In the summer months it warm enough that the straight 30w gives good start up protection, while being easy to start too..........Tom
     
  5. mezammit

    mezammit LawnSite Member
    Posts: 94

    Thanks for all the help yeah they do call for a straight30 weight oil. Hopefully this will solve my problem. Once again thanks for your help.
    Mike
     
  6. topsites

    topsites LawnSite Fanatic
    Posts: 21,654

    I would change the air filter just to be sure, if it's dirty it could be choking the engine which might be what's making black smoke.
     
  7. Den69RS96

    Den69RS96 LawnSite Member
    Posts: 96

    The synthetic oil is not thinner than regular oil. The molecules in synthetics have been changed to be more uniform in size where as reg dino oil contains large and small molecules. If your engine calls for 10w-30 you can use reg oil or synthetic. By making the molecules more uniform, synthetics will allow you engine to run smoother and cooler with less friction. However, most of the difference is in the additives. Synthetic usually have better additive packages in them. If your engine puffs out black smoke, its rich, white smoke is condensation, blue smoke is usually oil.
     
  8. mezammit

    mezammit LawnSite Member
    Posts: 94

    Well I changed the oil to a straight 30W and it is still smoking. Come to find out it is burning oil. I thought it was just running rich but nope it is burning it pretty good. This mower only has 160 hours on it now. I am starting to get fustrated with it. The only two things that I think are causing it to burn oil are the valve seals or the rings. The mowers warranty just ended. Any one else have any ideas of what would cause the mower to burn this oil with only 160 hours on it.
     
  9. action13

    action13 LawnSite Member
    Posts: 29

    Another mention on motor oil. And this is no more than my own theory, perhaps synthetic oil doesn't break down as quick as regular motor oil, and has a longer crankcase life with less frequent change intervals, I am reluctant to use it, for the simple fact, that if it stays in the crankcase longer what about microscopic metal Particles from the engine parts wearing, and the carbon deposits in the oil, these are not ALL trapped by a filter and produce more damaging particles in the oil. Regular motor oil gets changed sooner, these are eliminated quicker.
     
  10. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Posts: 917

    Who is THEY?
    Kohler specifies 10W-30 in their Command engines because of the hydraulic lifters.
    Is this a different engine?
     

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