expert help needed

Discussion in 'Tractors' started by rbig, Nov 1, 2004.

  1. rbig

    rbig LawnSite Member
    Messages: 112

    Got a situation I need some expert help with, so am calling on this group for that.

    I have a garden tractor with a K532 engine. This tractor runs absolutely great---when it runs. I mow approx 20 acres with it, so need it running during the growing season.

    I restored this tractor from the ground up a couple years or so ago. A friend who used to work for a big small engine shop rebuilt the engine for me.

    I have worked on equipment for years. I'm a good mechanic, but not so good as a diagnostician.

    What my tractor does is:

    1. Sometimes start, sometimes not

    2. When it starts, it runs great, and has full power.

    3. Runs for a random interval, then dies suddenly.

    4. When it doesn't start, it simply won't fire, even with a whiff of ether.

    5. After sitting for awhile, it will normally restart just fine.

    6. Generally, the run time gets shorter, while time before it will restart gets longer.

    The situation is very frustrating.

    Here's what I've recently done to it:

    a. new factory coil
    b. new points
    c. new plugs
    d. new plug wires
    e. new air cleaner filter
    f. electric fuel pump checks OK; sounds normal, and pumps a good stream when hose slipped off carb and pump run.
    g. regulator/rect unit seems OK; battery is charging fine, with just over 12vdc going in.

    My impression is that the problem may be temperature related, but not sure on that (as it will sometimes restart when hot).

    What's left to replace? Ignition switch (easy and cheap), and electric fuel pump (easy and not too expensive). What else that might cause this?

    Sure would appreciate some thoughts on directions I can head out in getting a good fix on this thing.

    I don't know this specific engine. Are there known issues with it that relate to my problem?
  2. Travis Followell

    Travis Followell LawnSite Silver Member
    from KY
    Messages: 2,206

    Sounds like vapor lock to me. When he rebuilt the engine did he replace the valves?

    An engine that vapor locks really bad a set of new valves helps the problem significantly from what i've heard. Personally I havn't had any experience with vapor lock but know a couple of people that have.
  3. xcopterdoc

    xcopterdoc LawnSite Senior Member
    Messages: 752

    These can be tuff.. BUT, there is hope! You need to be ready to troubleshoot the minute it wont start. Remember the basics... fuel, spark, ect.. When it cuts out and wont restart, check right away for spark and fuel. Find the missing link, then troubleshoot that system to find the problem.
  4. Travis Followell

    Travis Followell LawnSite Silver Member
    from KY
    Messages: 2,206

    That is exactly what you should do first.
  5. trailer landscaping

    trailer landscaping LawnSite Member
    Messages: 3

    If it won't start with ether, your eliminating fuel. If it wont start, check for spark.
  6. Travis Followell

    Travis Followell LawnSite Silver Member
    from KY
    Messages: 2,206

    Have you got it straightened out yet?
  7. olderthandirt

    olderthandirt LawnSite Platinum Member
    from here
    Messages: 4,899

    You asked for expert advise so I'll throw in my 2 cents worth. Take it to a shop with the tool and equipment to diagnose the problem. Just replacing parts and not accomplishing the task is wasting time and money

  8. dishboy

    dishboy LawnSite Fanatic
    from zone 6
    Messages: 6,270

    He asked for advice on how to diagnose the problem , which a few offered up.

    Next time it dies pull a plug and connect to a known good plug that you ground and then crank and you can confirm the above suspicion that it is electrical. If it has a bad condensor it can do what your describing I believe. I think you can check it with a ohm meter.
  9. rbig

    rbig LawnSite Member
    Messages: 112

    OK. It's fixed. The points were bad, and, in effect, the capacitor wasn't in the circuit through a mis-wiring by Watash. Couldn't believe I hamburgered that thing like I did. Oh well---all's well that ends well.

    Thanks for the words of advice and help.
  10. MBDiagMan

    MBDiagMan LawnSite Senior Member
    Messages: 852

    Rbig, glad you got it fixed. See there, you're a better diagnostician than you thought.

    For future reference, the suggestion to take it to the shop when it quits is, I'm sure, well intended, but incorrect. The people at any service department will just roll their eyes when you bring them something that only gives trouble SOMETIMES. An intermittent problem is the worst thing for them to troubleshoot. If it isn't broke when they look at it, they usually can't fix it. In Rbigs case, they might have fixed it, but usually not.

    Intermittent problems have a nasty habit of not acting up for the tech who is looking at it.

    My $0.02,

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