Need a little help.

Discussion in 'Mechanic and Repair' started by Bitter, Apr 24, 2006.

  1. Bitter

    Bitter LawnSite Member
    from Chicago
    Posts: 68

    It's been a while since ive been here since its been winter. I've got my neighbors rider here and im having a problem. Mechanically the engine is sound, awesome compression, turns over smooth, brand new carb (old one was rotten to the point where a rebuild wasnt worth it), new starter and battery. it cranks great...but (always a but) i dont have enough spark to get it to fire.

    its fired sporadically a few times during cranking, but never more than one pop.
    theres enough spark to cause a good jolt, but not enough to jump any kind of gap at all. theres a small (2" by 3" by 1/2" thick, i think its a rectifier/voltage regulator) box on the right side of the engine (sitting on the machine) with 3 wires that plug into it from under the flywheel. im not exactly sure what that does but it looks important. if anyone could give me any insight into this or assistance i would be highly appreciative.


    its a sears model # 917 255350 with a engine # 142 3296042. i used to have acess to service info and cross reference sheets to translate from sears to tecumseh engine numbers.

    this one has me stumped, im not sure whats going on to cause such a weak spark other than dirty/bad points and condenser system under the flywheel. but i really dread having to pull that. what else should i check?
     
  2. Paradise Landscapes

    Paradise Landscapes LawnSite Senior Member
    Posts: 960

    that rectifier- volt regulator charges the battery.
     
  3. Bitter

    Bitter LawnSite Member
    from Chicago
    Posts: 68

    cool, i figured it was something like that. its not too dissimilar from things ive seen in old alternators.

    can anyone tell me...
    what the tecumseh model is
    if its solid state or points/condenser.
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Well thats a VM100 Spec. # 157034B and it looks like you are pulling the flywheel and replacing points & condenser. Points Part # 30547A, Cond. # 610767A. And you read the engine number wrong it's a 143.296042.

    Good Luck
     
  5. oldrustycars

    oldrustycars LawnSite Senior Member
    Posts: 301

    Rob, what is this "points" you speak of? something used on ancient lawn mowing machines?
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Yeah Greg, They were used in all sorts of ancient internal combustion engines. :laugh:
     
  7. oldrustycars

    oldrustycars LawnSite Senior Member
    Posts: 301

    back in the 80's i was at a briggs dealers meeting. some guys had their panties in a twist BECAUSE of going to Magnetron. they just loved selling, and charging to install, points and condensors. i even still have the pliers thing to compress the spring on the condensor.
     
  8. Bitter

    Bitter LawnSite Member
    from Chicago
    Posts: 68

    i went a little dyslexic on that sears number :lol: thanks!

    i had a feeling it was points and condenser :( i dont know as much about those as most of what i worked with in school and at home are magneto type. ive seen a few points and condensor systems and worked on one a little bit but am none too familair with them. what would cause such a weak (almost no) spark? bad points? i do remember that the condensor is to help prevent the points from burning. hey, restrorob, is there a conversion for this motor? if so then i'll just shell out the cash and convert it to magneto and not have to muck with it. also can you tell me where i can find a spec sheet on it? numbers like clearances and compression are what i need.
     
  9. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

     
  10. Bitter

    Bitter LawnSite Member
    from Chicago
    Posts: 68

    thanks again, thats a bummer about it not being like briggs. i'll pull the flywheel tomorrow, lousy weather today.
     

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