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crazy lawnmower

Discussion in 'Members Lounge' started by mstechca, Jun 21, 2005.

  1. mstechca

    mstechca New Member

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    This season is the craziest for my lawnmower.

    The first time I used it this season, I had to remove the muffler and some other pieces, clean it out and put it back together before it wanted to start.

    now this time, my grass is long, and I can't start the stupid lawnmower.

    I checked the sparkplug and sanded as much of it as I could so that electricity can flow better. I replaced the plug last year.

    I checked the carbeurator and the primer button. All that seems to be working. I checked everywhere else I could think of and everything seems to be clean and in working order.

    I washed out the gas tank with water and refilled it with gas. I filled my oil.

    If I am lucky, I could get the lawnmower working for one second, and that's it.

    Please help ASAP, because this situation is annoying my entire family.
     
  2. D.J.

    D.J. New Member

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    Hi,

    Well if you checked all that, the only thing that I can think would be wrong is that maybe you are using some bad gas, or maybe when you sanded the spark plug you bend the metal just a little too much so it won't spark.

    Did you hold the spark plug out while you started it to see if it had a nice blue spark?

    This is all I can do to help :lol:

    Hope this will be of some help,

    D.J.
     
  3. mechie

    mechie New Member

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    engine trouble

    As per D.J.s post ... !

    All I can suggest is fuel and spark - the rest is just rattle, clanky stuff.

    Pull the spark plug, reconnect the lead and touch its body to the cylinder head so you can see any spark, crank the engine and you should see the spark, if not, check the gap- it should be maybe 30 thou (check your manual). If the gap is reasonable and there is no spark then you have either a knackered spark plug, a broken lead or a lack of HT. Is there a 'KILL' switch built into the throttle ?

    While the plug is out try putting your thumb over the hole it came from and turn the engine slowly, you should feel a good suction and a good compression, if not, you need to consider refurbishing the engine - piston rings and head gasket as a minimum; cylinder bore circularity (the bore wears oval eventually - "scrap the engine" time :? ) and crank shaft and conrod bearings need to show no 'slop', nice and snug.

    You say you checked the carb - is that just visual ?
    Could the jet in the carb be blocked, a small jet only takes a small amount of fluff/dirt to block it - strip the carb and wash the bits in petrol (keep Tails away :wink: ) - try to back-wash the jet to dislodge the crap.
    Clean any fuel filter or better still, replace it. Wash the fuel line and tank, it's pointless cleaning the carb just to clog it again.

    I regularly use petrol stored in a can (or left in the mower) from the previous year with no problems but some say never use old fuel :shock: (seems like a waste to me).

    Failing that, buy a new mower :wink:

    As an afterthought --- when ( :!: ) you get it running again --- after you have finished mowing, let the engine cool down and pull the spark plug again, look at its colour, this tells you if it is running too rich or too lean.
    Look at http://www.eric-gorr.com/techarticles/sparkplugs.html
    or
    http://www.nightrider.com/biketech/spkplghnbook.htm#We for a guide to colours. I often find two-strokes run best when they are just a bit rich, try to get them "spot-on" and they can be difficult to start when cold, I know this contradicts the "official" information but it seems to hold true for me.
     
  4. dave

    Dave New Member

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  5. zachtheterrible

    zachtheterrible Active Member

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    Check your gas filter.

    I have a little two stroke pocketbike that wasn't working (wasn't the first time, stupid chinese built) and the gas filter had a piece of the plastic hose that broke off in it. Worked fine for a little while after that, something went wrong again :lol:

    The gas filter in mine was in the gas tank, connected to a little hose that led to the carberatour.
     
  6. Roboticinfo

    Roboticinfo New Member

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    Check your piston and look for any damage there, also check the magneto which is a common problem with lawn mowers, all the problems you said pointed to the magneto.
     
  7. mstechca

    mstechca New Member

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    I replaced the spark plug with a brand new one, and the lawnmower still wouldn't start. I cleaned the gas tank with water earlier, and then I put fresh new gas in the lawnmower.

    I even changed the oil and it still didn't work.

    Is there some item I can easily purchase that magically removes water from the gas? I think there is one item that starts with an e or an m and is 5 letters long.

    What is the Piston, and what is the magneto?

    I am very unfamiliar with many engine terms.
     
  8. D.J.

    D.J. New Member

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    I didn't know what a magneto was until you asked, I did a quick google search and came up with this article from how stuff works:
    http://science.howstuffworks.com/question375.htm
    It's a high voltage generator that creates high voltage pulses instead of a continuous.

    A piston is a cylinder piece of metal that moves up and down inside a vesle containing fluid. I think it pumps the gas.

    I am new to this stuff too :(

    D.J.
     
  9. Roboticinfo

    Roboticinfo New Member

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    That is why you are not fixing the problem!
    In order to fix lawm lowers you have to no of every part from the lawn mower.

    Do you know how to take the whole engine apart including the piston and the connecting rod and put it back together?

    If you don't then I insist that you take it to a lawn mower shop.
     
  10. Roboticinfo

    Roboticinfo New Member

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    Sorry D.J. but you are wrong the piston go's up to the top of the crank case the spark plug give a shock and a explosions happens and forces the piston to go down the vavles open up and let out the exsuast and it repeats the step over and over again.

    Then it pushes a rod and that turns a shaft.
     
  11. mstechca

    mstechca New Member

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    I want to avoid the lawnmower shop, because they can cost alot of money.

    There has to be a simple solution. What is it?
     
  12. D.J.

    D.J. New Member

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    Hi Roboticinfo,

    Woops sorry :oops:

    Well at least I knew it moved up and down :lol:

    D.J.
     
  13. Roboticinfo

    Roboticinfo New Member

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    Replace the magneto
     
  14. Roboticinfo

    Roboticinfo New Member

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    See you did get that right

    I am so proud of I cant stop blushing :oops:
     
  15. zachtheterrible

    zachtheterrible Active Member

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    Try lookin for that gas filter. that solved the problem on my pocketbike and the problem on my pocketbike sounds exactly like what was goin on with your lawnmower.

    You have to know somebody that knows a thing or two about engines, take it to them and have 'em look at it with you.
     
  16. Roboticinfo

    Roboticinfo New Member

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    Zach it would be the magneto because he replaced the spark plug with a new one and still nothing. The magneto is what gives the electricty to the spark plug.

    I used to fix lawn mowers
     
  17. chiba

    chiba New Member

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    Ethanol and methanol obsorb water and mix with fuel. But with such a small volume i would not bother, just get rid of that fuel and then flush the tank, fuel lines and carby with fresh fuel. Lesson learned, don't wash your fuel tank with anything other than fuel.

    I don't think you have explained if you are seeing a spark yet? are you? also i see you wrote "replaced oil", i'm assuming it's a 4 stroke, right? while your plug is out put you thumb over the plug hole and spin the mower. is there a lot, very little or heaps of compression?
     
  18. Roboticinfo

    Roboticinfo New Member

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    If there is a spark then it is not the magneto but if there is no spark then it is for sure.
     
  19. chiba

    chiba New Member

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    Umm, if there is no spark it could be a lot of things, we will get to them when he answers the question, also i can see mechie gave an excellent responce and if it was followed properly he would not have put water in his gas tank.
     
  20. zachtheterrible

    zachtheterrible Active Member

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    He didn't say there isn't a spark!
     
  21. mstechca

    mstechca New Member

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    I put my thumb over the spark plug hole, and tried starting it. I couldn't pull the cord due to my awkward position. But I can feel a little suction until the pull cord retracts.

    I don't know exactly how to test for a spark, but I replaced the spark plug yesterday, so the spark plug should be no problem.

    The funny thing is that sometimes, the lawnmower works for 1/2 a second then shuts off.
     

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