Kawasaki FH721V 25 HP Problems

Discussion in 'Mechanic and Repair' started by Daves Propert Maintenance, Nov 27, 2007.

  1. Daves Propert Maintenance

    Daves Propert Maintenance LawnSite Member
    from USA
    Posts: 83

    I have a Ferris IS 2000Z 52" with Kawasaki FH721V 25 HP engine, purchased from my dealership about one year ago as a demo unit with full warranty. I am have problems with it when it is running. When I use it, I can get maybe 5 minutes of smooth running, then the engine starts to bog and surge. I stop the blades and lower rpms, and then it will stall completely, requiring choking to restart, even though it is warm. Then it will run smooth for enough time to mow maybe 30 feet, then it will start all over again, and the engine will not smooth out until it goes completely cold overnight, in which case it will only run smooth for about 5 minutes. I have completely replaced the gas with fresh gasoline, changed the spark plugs, and checked the air filter. The engine only has about 120 hours of use, with the oil changed every 40-50 hours. Please help me fix the problem so I can go back to work with the machine. I have not contacted my dealership yet on this, cause they will probably charge me for it and wanted to look here first. Any help/suggestions are appreciated.


    Thanks,

    Dave
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Dave,

    When it starts to surge apply the choke SLOWLY and see if it smooths back out. If it does your problem is most likely fuel related (trash/water in carb) in which this repair would not be covered under the warranty.

    If it doesn't smooth out then it could be ignition related which could be covered under the warranty.
     
  3. Daves Propert Maintenance

    Daves Propert Maintenance LawnSite Member
    from USA
    Posts: 83

    I will try that as soon as I get the chance. When I replaced the plugs I got a solid 45 minutes of smooth running out of the machine. I forgot to mention this, maybe it can help eliminate some possibilities. I replaced the original NGKs with Champions, and I noticed a slight, barely noticeable drop in RPMs, likely due to the different plugs I believe, but the problems came back after that first 45 minutes with the new plugs.
     
  4. Daves Propert Maintenance

    Daves Propert Maintenance LawnSite Member
    from USA
    Posts: 83

    Gotta bump this one up - need some help soon. thanks guys
     
  5. I MOW ALONE

    I MOW ALONE LawnSite Bronze Member
    Posts: 1,912

    did you try what rob said with the choke?
     
  6. Daves Propert Maintenance

    Daves Propert Maintenance LawnSite Member
    from USA
    Posts: 83

    I did, and it worked one time, but it wouldn't do it again. I can't actually try anything on the mower until friday as I am away from home at school, so I'm just looking for ideas so I can go all out on it when I get home. I have six clean ups to do this weekend and would prefer to use the ferris, but I can use the toro if I must.
     
  7. johnp900

    johnp900 LawnSite Member
    Posts: 71

    You did not post the spec # so I don't know which carburetor is on it, but check the carburetor vent tube if it is an externally vented carburetor. Most hang down & can get clogged with mud or dirt & not let the carburetor vent properly. It's an externally vented carburetor if there are two hose fittings on top of the carb. The larger one is for the fuel inlet & the smaller diameter is the carburetor vent.
     
  8. Daves Propert Maintenance

    Daves Propert Maintenance LawnSite Member
    from USA
    Posts: 83

    I'll make sure to check that when I get home. I will probably clean the carb out on friday, and hope this solves all of my problems. I would post the #s but I am 1 hour away from my equipment, so it'll have to wait.
     
  9. Fisher40037

    Fisher40037 LawnSite Member
    Posts: 36

    You should definitely check your valve clearances, pull the valve covers,
    carefully, and you can reuse the old gaskets. Check your rocker arms/studs
    for looseness, and check the clearances.
    It is routine maintenence anyway, and costs nothing to check, and is
    more than likely at least part of the problem.


    If it is not, then you have spent nothing, and your valves are adjusted....


    Fish
     
  10. lifetree

    lifetree LawnSite Fanatic
    Posts: 5,370

    Dave -- Sounds like an interesting situation, please let us know what results you get from these suggestions !!
     

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