smoking at an angle

Discussion in 'Mechanic and Repair' started by MV Property Care, Nov 15, 2005.

  1. MV Property Care

    MV Property Care LawnSite Member
    Messages: 169

    My 16hp Briggs & Stratton extended life series engines will puff some serious smoke whenever it is leaning down to the right. This is on my Quick 36. This has only happened twice and then I quickly try to level up. So I checked out the Briggs & Stratton web site for answers. In the FAQ's section, it said this will occur when opperationg engine at greater than a 15 degree angle. Well I will try to stay out of those situations but I would like to know what exactly is happening inside the engine and if it could cause permanent damage. Is the oil going to something that can't let something breathe and that cuts the engine out? After the last sentence you now know the extent of my technical knowledge. Anybody know? Thanks in advance, MV.
  2. Brianslawn

    Brianslawn LawnSite Silver Member
    Messages: 2,002

    vertical shaft? is it when its leaning toward the valves. if so to much oil is getting into firing chamber and burning. post in repair section and restrorob or fixer67 can help you more.
  3. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    It's probably just pushing oil through the block breather valve.
    These are usually plumbed into the carb/airbox via tubing.

    So when oil passes through, it gets sucked in with the gas.
    It will puff white smoke like a freight train until it clears.

    Check your air box, air filter and carb for any traces of oil.

    I really don't know any more to tell you about that engine though.
    I wouldn't think it would do that unless the angle was pretty extreme though.

    My advice to you is just to contact Briggs directly from their site.
    Or better yet, just give them a call in the morning.
    You will find they are great to work with.
    They will steer you straight.

    I can't say anything but two thumbs up about them and my commercial briggs engines.
  4. MV Property Care

    MV Property Care LawnSite Member
    Messages: 169

    Thank You for the info Brian and Envy
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    This smoking is caused because one cylinder is lower than the other. When ran more than 15 degrees on the lower cylinder side the oil in the crankcase runs into the cylinder behind the piston, As the piston travels back down the cylinder the oil that is puddled in the cylinder is pushed past the oil ring and causing the smoke. Change direction of mowing on the slope with the higher cylinder pointing down the slope and it may not be as bad.
  6. MV Property Care

    MV Property Care LawnSite Member
    Messages: 169

    Thank you Rob. I see you know your stuff. By the way is this common for most lawn mower engines or just this 16hp briggs?
  7. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    It's common on most when when put on extreme angles, Not just the 16 Briggs.
  8. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    To be honest, shame on me, but I have never even "looked" at a Quick 36 period. Not even online. But other responses in this thread had me scratching my head...

    So anyways, I went to their website and looked at their machine. As soon as the picture popped up I understood totally.


    Ferris does this on their walks also, as does Hustler on the Z's and the new Trimstars.

    The sucky but simple answer is just don't mow those areas with the trim side pointing down hill. Furthermore, 15 degrees is basically flat as far as I'm concerned. I hope the areas are steeper than that.

    Anyways, still go ahead and check that airbox because I'm still not 100% satisfied that is all their is to it. Could still be a weak or bad block breather valve.

    All these things aside though, how many hours are on the engine so far? Enough that it is well broken in and seated? What oil are you running?
  9. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Just wondering Envy, If there was a problem with the crankcase breather wouldn't you think it would smoke all the time and not just on slopes twice ?

  10. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Messages: 11,087

    Well... far be it from me to second guess the opinion of a Master Service Technician... LOL

    No now seriously, you would know way more than I would.... and the answer to your question I feel is "ordinarily.... yes"

    However, if there is one thing I have learned, it's that you rule out the simple to check stuff first, and always stop at the extreme of "wouldn't you think?" so as to never absolutely rule things out too quickly.

    But anyways, yeah, if one of those goes bad it usually will go all at once and it will smoke like an Alabama freight train. But at the same time, I've found oil in my airbox and carb a few times over the years at random after having them smoke like he describes. But I have to admit I was not concerned enough to dig any deeper. Usually figured I pushed it too far on the angle of operation or it was just a weak BBV but not a gone one.

    Lastly, I personally just have to think there is something more to it since we are only talking a 15 degree slope. With various engines I have operated at 2 times that angle without any problem.

    So in addition, I would also be considering the oil and the actual oil level.
    Could be the oil itself or the engine could be a hair over full.
    It could even be too full because of a short dipstick.

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