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Problems with Kawasaki 19hp

Discussion in 'Hustler Turf Equip (Archived)' started by wdb, Oct 4, 2004.

  1. wdb

    wdb LawnSite Member
    Posts: 16

    Hi all,
    I have an Hustler 44" Mini-Z with a Kawasaki 19hp engine that has started giving me some headaches. When new this engine literally purred, but for the past 20 or so hours of running time, it has developed an annoying surging at any speed below wide open throttle. The dealer has told me it is everything from normal, to my fault for the gas I use, to me not running the machine flat out all the time. There are times when I need the blade speed a little slower in my yard, and need to run the engine a little slower. I also like to let an engine idle for a minute or two when I start it to warm it up before opening it up to mow. The same is true just prior to shutting it off (Even the Kawasaki manual says to do this.) When this engine is idling, you can hear the RPMs go up and down and actually watch as the governor opens and closes the throttle as the engine sputters off and on. I pulled the plugs and noticed that the one in the cylinder closest to the seat runs noticeably leaner then the other. To pacify the dealer, I have tried different brands of 87 octane, 89 octane, 91 octane and even some 100LL aviation gas I normally use in an antique race boat. I'm sorry but I feel that the dealer is feeding me a line of crap. When he tries the machine he always runs it wide open. When I tell him to idle it down to hear the problem he tells me I should never run the engine below full throttle. I do NOT buy this one bit. My feelings are that the carb is either dirty, or has jetting that is marginally too lean. Anyone have any ideas?
    I am worried about frying a piston or burning valves. This engine has just under 50 hours on it and has plenty of power. It just won't run right at part throttle or idle. It has a new set of plugs, and the oil has been changed 3 times now and is mobil 1 10W 30.
    Bill B.
  2. Bigjim810

    Bigjim810 LawnSite Member
    Posts: 4

    I have read previously that Kawasakii engines are real particular about running bad if they have dirty air filters. Clean or replace your filter and see if it runs different. The Honda on my Z surges until it warms up then runs smooth as silk at any throttle. You may be right on the jetting, but look at the air filter just in case.
  3. wdb

    wdb LawnSite Member
    Posts: 16

    My original air filter was relatively clean with minimal dirt build up. I did fix the problem. I gave up on the dealer and decided to remove the carburetor myself. I have rebuilt thousands of automotive and marine carbs as well as the ones on my other mowers so I am experienced with the technology. The idle transfer ports for one of the two venturies was partially plugged. I blew it out with a spray can of Gumout and this fixed the problem. Although the engine would run at or near wide open throttle fine, carburetors are designed that the idle circuit still delivers a small ammount of fuel even at wide open throttle. The loss of this is enough to make your engine run a little lean. Thus the reason for the one cylinder having a plug that burnded almost ghost white while the other looked fine. For others who experience surging and rough idle, remove your plugs and check to see if they are burning different as in my case. Next see if they look to be buring too clean and hot. If so you must have your carb cleaned out. Air cooled engines do NOT like to run too lean. They can run too hot and in severe cases dammage internal parts. These engines should idle and should run smooth under load at part throttle. Carb problems are quite common with these engines, but the good news is that the carb is not bad to service. It is simple and not very hard to remove.

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