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Mower coil resistance value

Discussion in 'In the Garden' started by ipbr21054, 6 Sep 2020.

  1. Burnerman

    Burnerman

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    Over ride the governor by holding the throttle butterfly almost wide open - and keep it there for a minute or two.
    What happens.....does the engine die after a while?
    John :)
     
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  3. ipbr21054

    ipbr21054

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    From memory even when I was trying to use a screwdriver to adjust the spring loaded screw you can help to touch the govner arm etc and it started to act up.
     
  4. Burnerman

    Burnerman

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    Over riding the governor causes the engine to rev higher than normal, naturally enough. If the engine dies when trying this, it is still short of fuel.
    John :)
     
  5. ipbr21054

    ipbr21054

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    Just found a carb so hopefully good news soon.

    will keep you updated
     
  6. Harry Bloomfield

    Harry Bloomfield

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    Checking the resistance doesn't help that much, because even if the value is correct, the coil is still not bound to produce a spark - There is still the possibility that the coil is breaking down under high voltage. The way to be certain of the spark, is using a spark plug, with the body firmly grounded against engine, as suggested by Burnerman - one person cranking it over, whilst another watches for the spark. Sometimes the spark can be made more obvious, by opening the gap up a little on the old spark plug used for testing.

    An old trick I learned for making the spark easier to spot, was to make up a short HT lead with a croc clip on the end to clip onto engine, cut in half, with a tack pushed into each end, then joined with a bit of clear plastic tube, but left with a suitable gap between the tack heads. The other end of the lead has a nail or screw inserted in it, so it plugs into the plug cap.
     
  7. Burnerman

    Burnerman

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    The mark of a man in my day was to grip the end of the HT lead and see how high you jumped when someone turned the engine over :eek:
    Maybe this engine never performed well.
    John :)
     
  8. ipbr21054

    ipbr21054

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    Ive used another coil but never any difference. Also new plug. Also plug to engine. Also plug tester between HT lead and plug.

    Sparks all the time.
    When I measured with meter the reading is the same. The second could is also near enough the same reading.

    I was led to believe the higher the reading / resistance the poorer the spark.

    When it was spluttering etc tonight like in last post or two a press on the primer button would boost the revs and run again.
    This wouldn’t of happened if it was ignition related.

    I’m going to fit the carb as this mower isn’t going to beet me.
    it’s a pain yes but I want to know the answer now.
     
    Last edited: 20 Sep 2020
  9. Burnerman

    Burnerman

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    The coil is fine....
    It wouldn't be the first time I've fitted a replacement carb to find it was a bloody dud either!
    Thinking about your last comment about pushing the primer bulb, this shows it is a fuel issue....not enough juice in the float bowl, to be exact or a blockage in the main jet. Don't worry about using fuse wire to clear the jet, it won't do any harm.
    John :)
     
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  11. ipbr21054

    ipbr21054

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    OK

    These are the only jets with holes in.

    Blue arrow has 3 holes & i think it controls fuel that enters the carb / float.

    Red arrow has 2/3 holes & i think its where the fuel enter through it & up the emulsion tube.

    So far never been able to remove emulsion tube but straight up the middle is 100% clear
     

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  12. ipbr21054

    ipbr21054

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    So to recap main jet is ered arrow correct ?
     
  13. Burnerman

    Burnerman

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    The blue arrow indicates the slow running fuel supply. (pilot mixture, if you like).
    The red arrow points to the main jet which must be completely clear.....above it is the float needle jet.
    The emulsion tube may have an obstruction if it has drillings into the side of it, but as you can't remove it we'll never know.
    John :)
     
  14. ipbr21054

    ipbr21054

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    Ok
    I put up a video with me leaving the main jet out,ok it was rough idle but i did it to give it more fuel.
    Can see video now & wont play either my end.

    I tried to press with flat screwdriver the top of the emulsion tube hoping it would pop out but it was very very tight so it never moved.

    When this other carb arrives im going to swap 1 item at a time to see which is the culprit.
    If the main jet is left out when started does that rule out emulsion tube ?

    There is the smallest of holes in this main jet & trying to squirt fuel through it is a big ask.

    I believe there are say 1/2 in the side of the jet & 1 straight the middle.

    What if i opened up the one throgh the middle but even then a big ask
     
  15. ipbr21054

    ipbr21054

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    Here is the carb on the way to me.
    Slightly different but same mower model

    RED ARROW..........SLOW RUNNING / PILOT

    GREEN ARROW...........??????????

    PINK ARROW.............MAIN JET
     

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  16. Burnerman

    Burnerman

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    Leave the main jet alone....just make sure it is completely clear. Leaving it out will allow far too much fuel into the engine and that will be hopeless.
    I can't say that the emulsion tube has any cross drillings - but as its jammed in place so leave it be. Forcing the thing out is likely to damage it.
    Lets leave things until you fit the new carb!
    John :)
     
  17. Burnerman

    Burnerman

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    Red arrow - pilot jet underneath, incorporated in a brass screw and not adjustable.
    Green arrow - pilot jet fine tune.....often one full turn out from fully in.
    Pink arrow - the ever important main jet.
    John :)
     
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