Any possible link between coil and PTO?

Discussion in 'Lawn Mowing' started by Envy Lawn Service, Aug 2, 2007.

  1. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    I have a Kawasaki that is missing pretty bad and hunting a little.

    I didn't get home in time tonight to mess with it much. But when I pulled the right plugwire it almost fell flat. I pulled the left and the hunting stopped, and it settled out well running on one cylinder.

    On this same machine, the PTO has failed to engage a couple of times intermittently over the past two weeks and then return to working normally.

    I'm thinking bad coil... which would explain the miss... and low charging could be the issue with the electric PTO.

    What say you?
     
  2. KTO Enterprises

    KTO Enterprises LawnSite Bronze Member
    Posts: 1,286

    I have had problems with dirt getting into electrical connectors on my mowers and causing problems. Most mowers have one big plug that connects the switch panel to everything else. Check your connections there. You could be getting a voltage loss. Also check battery connections. and battery ground cable. Most all electrical problems on any motorized vehicle is caused by connector issues
     
  3. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    I fiddled with all the connections I could get at.

    I changed the plugs and the fuel filter.
    At first I thought that settled it out.

    But it didn't.

    Best I can tell it's running OK above 3,000 RPM. (it may not be because I'm not using it)
    But below that it's missing and hunting/surging.
     
  4. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Ignition coil is shot, new one is about 45 - 50 bucks. The cylinder that you pulled the plug on and it fell flat on its face is O.K. the other sides coil will need to be replaced simple procedure really just remove the plastic shroud from top of engine and remove screws holding old coil in place / replace with new coil use a business card to set air gap.
     
  5. ealbertson

    ealbertson LawnSite Senior Member
    Posts: 256

    Swap the coils and see if the problem follows the coil or stays with that cylinder. As far as the PTO they will pull a lot of current when they fail sometimes which could make it appear like the motor isn't charging. I had a PTO go like that on a Lazer Z. I it burned up the brake safety switch twice (so much current through it) before I figured out it was the PTO.
     
  6. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    I appreciate the additional replies guys.

    I've never had one do quite like this.

    For me, usually the coils just fail flat out and it goes to one cylinder like bam.

    The only exceptions to this I can think of is that once I had an engine that seemed to run fine, but fall on it's face under load... like it lost torque.

    That one puzzled me and I took it to the shop. It turned out to be a coil that was firing and firing all the time, but putting out a weak spark.

    Another time I had one that would run fine until you kicked the electric PTO on. As soon as you did it would start missing like crazy. Another weak spark issue.

    Seems to me like that both of those times the mechanic told me something like he could tell by the color of the fire/spark when he arced it off something. I might be wrong about that, but I could swear it. Anyone ever heard anything like that?
     
  7. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Just for the heck of it, today I put some STA-BIL in the tanks and ran it for a bit to rule out water... and I doubt it's anything in the carb, because it has the canister filter, and the STA-BIL has carb cleaner in it.

    So, I believe you are right.....
    The only thing is that the air gap is HUGE as-is... way beyond the typical business card air gap.
    Ever seen one like that?

    I believe I am going to swap like you say just to double confirm to save time and tail chasing.
     
  8. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Well fellas... I called where I was going to go get the part from. They didn't have it and said they would call me monday to let me know about price and arrival. No biggie, didn't call anywhere else.

    I went ahead on and swapped those coils from one side to the other.

    At first it didn't seem to make a bit of difference.
    It even reacted the same to removing the plug wire on the same side.
    Like indicating it wasn't the coil.

    So I'm standing there scratching my head about what else it could be that would just effect the left cylinder even with the coils reversed. It was sitting there running with the cover off. Then it just seemed to settle out quite a bit.

    I backed it onto the grass and engaged the PTO several times at idle.
    It was able to engage the blades without stalling out at idle.

    I'm puzzled now.
    I might use it to mow my own lawn later on today or something just to see how it goes.
    Beats me...
     
  9. Envy Lawn Service

    Envy Lawn Service LawnSite Fanatic
    Posts: 11,062

    Oh, and I take this back too...

    ... it's hot out there and I was just looking at it the wrong way.
     
  10. deason

    deason LawnSite Member
    Posts: 236

    Depending on which Kawi it is, You may need to re-direct your focus.... here's why.

    Last year we had a 23 Kawi with close to the same symptoms as you describe. We replaced plugs and coil packs with no success. Then we replaced carb. NO LUCK. One would think after replacing all this, the problem would go away, it didnt.
    After some dead end calls to Kawi, we finally talked to a dealer who told us to check a couple of simple but important areas.....
    The model Kawi we have has a carb that is EXTERNALLY vented from the bottom of the carb. The vent tube is run to a specific location on the carb and is cut to a precise length per the specs of the carb and motor. We found the vent tube and gave it some adjusting. The motor smoothed up and gained RPMs but not completely. We then found that the motor speed and sound would change slightly when we moved the air cleaner cover. We replaced the air filter and the motor ran fine.

    This is what we learned - we usually checked the air cleaners on the machines periodically (weekly) and cleaned as needed. Now, we blow all filters on all machines DAILY with compressed air BEFORE they show signs of distress. Even a small amount of air flow restriction will cause long term problems if not addressed. Just because the filter doesnt look dirty doesnt mean it isnt.

    As for the PTO issue, we learned this one the hard way to but I will skip that story and give you this fact....Most if not all PTO switches are the first link between the switch and the starter. This means that The mower will not charge its battery or in our case start and run if the PTO switch goes out. Remove all doubt and change the $20 PTO switch.
     

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