smoking engine

Discussion in 'Mechanic and Repair' started by newblade, Jun 27, 2005.

  1. newblade

    newblade LawnSite Member
    Posts: 162

    Has anyone ever had an air filter clog up and cause the engine to start smoking, fairly bad? Mine started smoking a little at the beginning of the yard and was smoking bad at the end. I talked to a man about rebuilding the engine and he told me first to change out the air filter. I took it completely off and it did seem to help. I mowed about 45 minutes without any filter. I bought a new filter today and I am hoping that this will work. I also have a mower that will just click click when you try to start it??? I changed out the relay with the two bolts on top and still the same thing :dizzy: any ideas?
  2. LightningLawns

    LightningLawns LawnSite Senior Member
    Posts: 279

    check your wires to your battery
  3. drmiller100

    drmiller100 LawnSite Senior Member
    Posts: 562

    clogged filter causes them to run pig rich. pig rich means it smokes a lot.

    change your oil. sometimes the extra fuel gets past the rings if you persist in running it.

    for the electrical issue, find the starter, and jump start right to the big wire. sparks will fly. if it starts, then it is a safety switch issue or wiring or something. if no start, then needs a new starter.
  4. CCWKen

    CCWKen LawnSite Member
    Posts: 113

    There's a crankcase breather on most engines. It's a tube that runs from the engine crankcase (usually the valve cover) to the filtered side of the air. If the air filter gets clogged, the intake stroke will pull air from wherever it can. More times than not, it pulls the air from the crankcase which is full of oil vapor.

    It's not a good idea to run an engine without an air filter. You're pulling dirt and other material into the combustion chamber and your oil. One small pebble can ruin your engine.
  5. arborguy

    arborguy LawnSite Member
    from KY
    Posts: 14

    Mowing for 45 minutes without an air filter would introduce a lot of junk into your engine. I'd get a filter on there pronto and change the oil.

    Regarding the smoking, I assume we're sure the crankcase isn't overfilled. When you refill the crank I'd measure the amount on the engine spec sheet and see if the dip stick matches. I've seen incorrect dipsticks in engines before, especially used ones.
  6. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Perhaps it is possible you got too much oil in it? Check that.
    Then, put a new air filter on there and keep it there, lol, you shouldn't run them without. Once you're done with that, also replace the spark plug just in case (could be fouled) and make sure the gap is set correct.

    Maybe start running Amoco premium, that's all I ever use, doesn't cost much for a lawnmower but the benefit is well worth the extra few cents it costs to fill a small tank.

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