Lawn tractor help

Bad Wolf Posted By Bad Wolf, Aug 10, 2008 at 11:46 AM

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  1. Bad Wolf

    Bad Wolf
    Minister of Fire

    Jun 13, 2008
    522
    45
    Loc:
    Eastern CT
    If it isn't one thing it's another. While taking a break from stacking firewood, I was mowing the grass, when suddenly I get this hugh cloud of smoke and a clattering sound out of the engine. I'm thinking a hole in the piston and/or broken connecting rod. This is a briggs & stratton 18 hp OHV engine. How hard is it to open up and replace a piston? Or pull the head for that matter. Then I can at least see what I'm dealing with.

    Just what I didn't need right now.

    Thanks
    Greg H
     
  2. cmonSTART

    cmonSTART
    Minister of Fire

    Nov 29, 2007
    2,284
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    Loc:
    Antrim, NH
    Pulling the head shouldn't be too too bad. It will just be a matter of pulling all the shrouds and covers off, the valve cover off, and then unbolting the head. Replacing a piston is another matter. For that the engine needs to come off the tractor and then be stripped down. The shrouds have to come off, the head, maybe even the flywheel. The crankcase is split at the seam and the piston comes out the bottom after unbolting the rod from the crank. Good stuff.

    You may be able to see something through the spark plug hold. A compression test will also shed light on the situation. Depending on what tractor it is and what kind of engine, it may be more cost effective to just swap the engine out with a new one. Some of the cheaper engines are like that - cheaper (or close) to replace rather than fix.
     
  3. Bad Wolf

    Bad Wolf
    Minister of Fire

    Jun 13, 2008
    522
    45
    Loc:
    Eastern CT
    This keeps getting stranger. I pulled the head: no damage, turned it over by hand and couldn't see anything wrong. Put it back together and fired it up. Seem to run fine. Now I did notice a little smoke when I engaged the blades, and when it crapped out yesterday I was in some very heavy grass.
    I havn't done a compression test, what should I be seeing for a small engine?

    I'll keep my fingers crossed.

    Greg H
     
  4. savageactor7

    savageactor7
    Minister of Fire

    Jan 25, 2008
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    Sounds like a tad to much oil in the pan to me.

    If you were at high RPM's and quickly backed it off...the air filter could have sucked up oil. That's not a big problem either replace the filter, or clean it out with a gas or soapy solution and let it dry a day or 2 and put it back in.

    Did you recently top off your oil?
     
  5. Bad Wolf

    Bad Wolf
    Minister of Fire

    Jun 13, 2008
    522
    45
    Loc:
    Eastern CT
    Funny you should mention that. Yes I did just change the oil. Now that I examine the data label under the cover I think I refilled it with 56oz instead of the 48 it calls for. I drained some oil out so it shows full by the dipstick. We'll see how that works out. I'm just glad it wasen't the piston or rod.

    Thanks

    Greg
     
  6. Hogwildz

    Hogwildz
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    Nov 3, 2006
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    I'm with Savage on this one, too much oil is almost as bad as not enough.
     
  7. pdboilermaker

    pdboilermaker
    New Member

    Nov 7, 2007
    140
    0
    Loc:
    North Central Indiana, Kokomo
    Sometimes on a Briggs engine (or any other presumably) if you have too much oil, it can blow past the rings and too the top of the piston. If that happens, you will need to rplace the rings
     
  8. Bad Wolf

    Bad Wolf
    Minister of Fire

    Jun 13, 2008
    522
    45
    Loc:
    Eastern CT
    Why? Does it damage the rings? Would adding one of those thickening agents help? It seems to be running OK now. I assume the only way to get at the rings/piston is to split the case, which is more work than I have time for right now.

    Thanks for everyones help

    Greg H
     
  9. Highbeam

    Highbeam
    Minister of Fire

    Dec 28, 2006
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    There is a crankcase breather tube that dumps the fumes (and in your case maybe oil) right into the intake manifold or the air filter housing just ahead of the carb. This vent will puke enough oil into the intake to hopefully relieve the pressure before blowing rings or seals somewhere else. At this point you've checked the oil and it is correct so just run it.
     
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