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crazy lawnmower

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

  1. tansis

    tansis New Member

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    Check the carberetor , odds are the float chamber is full of water.

    As water is more dense than petrol , when you refilled the tank any droplets on the inside would of been displaced to the bottom and been the first thing through the pipe to the carb.
    A classic symptom is that the engine will run at tickover but dies when you crack the throttle open.

    Another thing to consider ...
    just how old is the petrol you used?

    storage containers are sealed but the fuel tanks for engines have a breather pipe to the atmosphere to equalise the pressure, last years gas in your mower would have "boiled off" some of , if not all the lighter fractions that make for easy detonation. As a rule of thumb fill a "zippo" type ciggarette lighter with the suspect fuel (observing the makers safety rules) if it wont light then the fuels useless.
     
  2. mstechca

    mstechca New Member

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    Why do you care?
    I changed both my oil and fuel before I even posted about this subject.

    Is it better if I use a piece of paper instead of a business card?

    and is the objective just to barely slide the paper or card through the contact points in the magneto circuit?
     
  3. Roff

    Roff Well-Known Member

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    Re: reply

    You may be right, but a new spark plug doesn't fix a clogged fuel filter. Seems like Zach's suggestion is worth trying.
     
  4. dave

    Dave New Member

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  5. Roboticinfo

    Roboticinfo New Member

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    reply

    No use the business card a paper is to thin
     
  6. Roboticinfo

    Roboticinfo New Member

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    Re: reply

    Of course it is worth trying, when fixing engines you got to try everything that could be a possibility.
     
  7. chiba

    chiba New Member

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    Given you have a spark already there is probably no need to concentrate on that side of things, But for the record a gap of 5-15 thou is good enough, losen the coil mounting screws, put a feeler gauge of the right thickness between the coil and flywheel magnet and let the magnet hold the coil up against the feeler, then tighten the coil and remove the feeler gauge.

    If you have a seperate oil and fuel tank then it could be a 2-stroke with an automatic oil pre-mixer?, very much like most chainsaws.
    If you are referring to an oil tank on the engine then it may be the crankcase of a 4 stroke that you are referring to?

    It may be helpfull to all of us if you were to take a pic, give its model and brand numbers or ask a friend to have a look for you. If non of that is available then a google image search of "lawnmower" may show up the one you have.

    If you decide to buy a new lawnmower, can i suggest this type, you will never have to worry about it starting :)


    [​IMG]
     
  8. Roboticinfo

    Roboticinfo New Member

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  9. mstechca

    mstechca New Member

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    Why do you care?
    I managed to make the coil and the flywheel so close together, that only two sheets of lined paper can go through. at a time without a problem.

    I'm thinking now it is the gas pump because when I was working on the carberator pump, I used a soldering iron to expand the rubber. the rubber didnt break!

    but my soldering iron accidently went on the plastic which is part of the gas pump. I also saw a small metal ball where the hole is.

    Is it normal to have a small hole there, or no hole at all?

    Maybe this is the reason why it doesn't start.
     
  10. bryan1

    bryan1 Well-Known Member

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  11. Roboticinfo

    Roboticinfo New Member

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    Thanks
     
  12. mechie

    mechie New Member

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    Surey not ?

    I think that is totally uncalled for and hope you have the humanity to see the error in your ways.
    It would be an outrage to burden a poor caprid like that, don't you have any rats that need a name ? :wink:
     
  13. Roboticinfo

    Roboticinfo New Member

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    Re: Surey not ?

    I find his comments amusing
    I like to hear what other people think of me.

    Thanks for the back up though
     
  14. chiba

    chiba New Member

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    Actually, the term magneto was first coined to describe the use of "magnets" to generate the power in an ignition circuit instead of a battery. Nowadays, modern small engines can have cdi, hei and various other types of ignition systems that on the outside appear to be very much the same in looks as a coil in a "magneto" sytem. It's not uncomon to find a diode(s), capacitor(s), SCR (inplace of points) a trigger winding for the SCR, an energiser coil as part of the "magneto winding", the primary HT winding and the secondary HT winding to the sparkplug. I have modified a few so called "magneto" sytems to remove the rev-limiters for racing purposes to allow many more rpm's, it's basicly a low pass filter also hidden inside the coil of a "magneto" ignition. The tricky part is getting the epoxy off and vacuum potting it together again to remove all the air bubbles. I mentioned in another thread, the one where you referred to me as a newbie! that my mate built me a vacuum potting machine so we can build our own "magneto" and HV coils.

    lol, I'm definately calling this one robotinfo:




    [​IMG]
     
  15. Roboticinfo

    Roboticinfo New Member

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    Ohh so how is your [EDIT]

    How often does he make you vacum potting machine?

    You guys must [EDIT]

    Anyway I called you a newbie because you were bad mouthing my friend Digitan and you wouldn't leave him alone. [EDIT]

    EDITED by MOD, Jay.slovak
    Please by polite to your fellow members!
     

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