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testing for spark

Discussion in 'Mechanic and Repair' started by ACA L&L, Dec 20, 2007.

  1. ACA L&L

    ACA L&L LawnSite Bronze Member
    Messages: 1,102

    Is there any easier way to test if a blower is getting a spark, other than putting your finger on it and getting zapped. One of me blowers just wouldnt start today, it has compression, took the carb apart looked good, the only thing i can think of is that its not getting any juice.?
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Ain't no way I'm stickin my finger on ANY plug wire. :nono:

    Remove the plug then plug it back into the wire boot, Hold the hex part of the plug body to any metal surface on the unit and pull the rope. If a nice blue spark jumps the gap on the plug it's firing good.

    There are many different types of spark testers on the market for as little as $15.00.....

    BTW, How's the Walker ?
  3. EustisGoober

    EustisGoober LawnSite Member
    Messages: 4

    You must be kidding!?!?
    Grab the plug? Wow, thanks for the laugh. Restrorob has the right idea.
  4. ACA L&L

    ACA L&L LawnSite Bronze Member
    Messages: 1,102

    Im glad you think its funny. I on the other hand prefer not to get zapped, on purpose any way.

    The walker ran all day today without any problems! My money is on the fried connectors and wires touching causing the engine to shut down. Go figure, never would of thought to check the control box unless there was smoke coming out of it. Thanks again for the help.
  5. EustisGoober

    EustisGoober LawnSite Member
    Messages: 4

    lawnzilla2, not laughing at you getting zapped just the situation. Getting zapped by accident only needs to happen once then you take precautions. With todays systems, they can pack a punch so be carefull. Restrorob had a good idea. I work on cars and enjoy reading the posts. I help my son maintain his equipment. I don't have the training history that Restrorob has. I do read his posts and from afar he knows what he's talking about. If I was checking for spark I use the tool that was mentioned. Try this link to eBay, http://cgi.ebay.com/ebaymotors/NEW-...013QQitemZ230204380468QQrdZ1QQsspagenameZWDVW. This will work on your mower to your monster truck! There are different tools out there also if you want to carry it further.
    In a case like you mention, after the unit not starting I would pull the plug to see if it was wet, if so clear the chamber, install a known good plug and retry.

    I'll stay tuned in to pick up tips on my Dixie, JD, Stihl equipment. RestroRob,, the floor is yours.
  6. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 949

    For many of the newer engines with "electronic" spark generation, I strongly recommend a spark tester.
    Holding the plug next to the engine can sometimes be rather hit or miss. Often the coil will try to keep building voltage when the plug is not grounded. This can cause the coil to break down internally, because the voltage is trying to find a path to ground somewhere. IF the path of least resistance is adjacent coil windings, it'll try to jump there. Sometimes successfully! That results in a "fried" coil.
  7. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    But Bill,

    I have had twins come in with a lack of power complaint, I found one plug wire off dangling. I replaced the wet plug and plugged them back up and sent them back out.

    Another thing, My boss's son used to race go-carts (5hp Briggs), Not one at the track had a kill switch. They all put a zip tie on the plug boot and used it to snatch the plug boot off to shut them down.

    If the steel hex shaped body of the spark plug is held in contact with a engine block ground (head in most cases) this is grounding the plug. ;)

    Also, It doesn't require but one pull of a rope (2 to 3 revolutions) to check for spark so I see no way to fry a coil in one pull just checking for spark.
  8. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 949

    On page 8.8 (124/217) of the Kohler Command service manual (tp_2450_b)

    "Test 2. Test for spark.
    1. With the engine stopped, disconnect one spark
    plug lead. Connect the spark plug lead to post
    terminal of spark tester (see Section 2) and attach
    tester clip to a good engine ground.
    NOTE: If two testers are available, testing can be
    performed simultaneously for both cylinders.
    However, if only one tester is available, two
    individual tests must be performed. The side
    not being tested must have the spark plug
    lead connected or grounded. Do not crank
    the engine or perform tests with one spark
    plug lead disconnected and not grounded or
    permanent system damage may occur."
  9. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    I don't doubt that possibility at all Bill, On a twin cylinder.

    The unit in question is a single cylinder blower, As said if the plug is grounded I don't see the above happening on any single cylinder engine.

    Oh, I only recommend this procedure to ones that need a quick system check and don't have a spark tester. I have 5 different styles I use for my testing.

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