Kawasaki FS481v backfiring and sputtering - help

Discussion in 'Mechanic and Repair' started by BIGDOGMN73, Aug 5, 2012.

  1. BIGDOGMN73

    BIGDOGMN73 LawnSite Member
    Posts: 32

    My Kawasaki FS481v starts perfect (half pull) seems just fine when I first start. After it starts to get warm it starts to sputter and has a little backfiring. I've noticed that when the blades are engaged and I'm mowing it doesn't do this. If I just have it in transport mode or just sitting there it starts to sputter/backfiring. I've replaced the spare plugs, hooked up a spark tester and that shows nothing wrong (ignition coil). I did think one of the ignition coils was bad as when I was testing it I had the mower on, I removed the right spark plug connection and the engine RPM dropped and had a little sputter. When I did the same process on the LEFT side there was no drop in RPM so I assumed that ignition coil was bad. I thought I would test it first before spending the $50 for the part so I got that inline spark tester and the "light" showed the same thing for both. I don't think the issue is the fuel filter as I would think it would run weird all the time with that. The mower is only 2 years and I'm the second owner so I'm not sure about any other adjustments the previous owner made. Value adjustment time? I honestly have no clue, but could use some help on this one as I don't feel like taking it in. It still runs really STRONG outside of this.
     
  2. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Sounds like the choke is sticking...staying partially choked...
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  3. BIGDOGMN73

    BIGDOGMN73 LawnSite Member
    Posts: 32

    So I was playing with the choke, but no luck. Any other idea's?
     
  4. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Wouldn't hurt to check the valve adjustments..
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  5. larryinalabama

    larryinalabama LawnSite Fanatic
    Posts: 16,451

    I had a "casting" plug come out of the top of my carburator reciently causing the same symptoms.
     
  6. BIGDOGMN73

    BIGDOGMN73 LawnSite Member
    Posts: 32

    When it comes to the engine I have to admit I'm not a pro yet. For adjusting the values is that something I can do on my own? I guess I can check it out on the forum, etc.

    For the casting plug where is that located on the carb?

    Thank you both for your idea's...I'll dig into them.
     
  7. larryinalabama

    larryinalabama LawnSite Fanatic
    Posts: 16,451

    If the plug came out you can see "brass" in a hole after you take the air cleaner off.
     
  8. pugs

    pugs LawnSite Gold Member
    Posts: 3,023

    Possibly intake gaskets. I have heard they have had some trouble with them.
     
  9. BIGDOGMN73

    BIGDOGMN73 LawnSite Member
    Posts: 32

    So what's the plugs name like in a parts list. I searched for it and nothing. One other note that I just noticed today...it only does the backfiring at FULL throttle.
     
  10. larryinalabama

    larryinalabama LawnSite Fanatic
    Posts: 16,451

    Heres the deal.
    I had the same symptoms as your having.
    I changed the spark pulgs because I figured after 800 hours it might need it anyway, made no difference. So I took the air cleaner housing off and saw the casting plug had had came out,,,

    I dont know if the plug comes in a curaburator kit, but the curaburator is 180$ and Im cheap so I thought about how to fix it.

    The main carburator jet goes through up to where the plug goes and it looked like there were passeges so some sort of plug was neccesary.

    I wound up <DONT LAUGH> taking a small split lead fishing weight and breaking it in half filed on it till it could be tapped into the carburator, then took some 2 part epoxy and put it on top so the plug wont fall out. It has worke for about 6 weeks so Im sure its a permant repair.
     

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