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Surge from 15HP Kawasaki

Discussion in 'Mechanic and Repair' started by genesis215, May 8, 2008.

  1. genesis215

    genesis215 LawnSite Senior Member
    Messages: 795

    My 15HP Kawasaki FH-451 is surging slightly, the rpm goes up and down, and it does it even when fully warmed up. Sometimes it does not do it. What do you think the problem might be? Spark plugs? I took one out and it was very dark in color, and dirty; possibly not gapped right too. Could new spark plugs fix it? It is likely a high-hour engine too (there is no hour meter on it). I hope it will be something simple to fix. Do you have any advice?
  2. jkilov

    jkilov LawnSite Bronze Member
    from MS
    Messages: 1,415

    Check governor linkages and springs. Make sure the joints are clean and levers move freely.

    Also try adjusting carb mixture screws. Could be set too lean.

    Sometimes mounting a heavier blade helps.
  3. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    What spark plugs were in the unit and what was the gap set to? How many hours and how many valve adjustments, how often is the oil changed and what grade is being used and lastly what condition is the air filter in?
  4. genesis215

    genesis215 LawnSite Senior Member
    Messages: 795

    I put new spark plugs in, and that pretty much fixed it. Praise the Lord!
  5. mowingguy

    mowingguy Guest
    Messages: 0

    replace the air filter. seems my Kawasaki likes them super clean. -SL
  6. genesis215

    genesis215 LawnSite Senior Member
    Messages: 795

    Well, now I have a 17HP Kawasaki on another mower that is doing the same thing, only worse. It smoothes out somewhat after the engine warms up, but still has a distinct miss to it. I took the plugs out, and both were almost new, one was very good, but the other one looked like it had oil all over it. Does this mean that I have a worn out cylinder, piston rings, or even carboned-up valves? It seems to be alot worse when it's cold. When it first starts, one cylinder fires, and then the next one fires and emits grayish smoke (perhaps because of the leaking oil into the cylinder). Also the exhaust smells REALLY odd; maybe it's burning oil in that one cylinder. What do you think is going wrong, and what do you recommend I do to fix it? It's winter, so it's a good time to be rebuilding an engine or working on it. Thanks for your help.
  7. RonAyersMotorsports

    RonAyersMotorsports LawnSite Senior Member
    Messages: 854

    Replace plugs and air filters. If problem continues carb needs to be cleaned and fuel filters replaced.
  8. nimrod

    nimrod LawnSite Member
    Messages: 24

    What kind of oil do you use do you use on your 15HP?
  9. RonAyersMotorsports

    RonAyersMotorsports LawnSite Senior Member
    Messages: 854

    30W High detergent. Brand doesn't matter as much. Long as it's not the cheap stuff.
  10. nimrod

    nimrod LawnSite Member
    Messages: 24

    Thanks. Just bought my first commercial WB with a 13hp Kaw. Changed the oil last night with Valvoline SAE10W30 non-synthetic and woke up this morning worried if I should have looked into some sort of special mower oil...

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