19 HP Kawasaki FH601V engine hp upgrade?

Discussion in 'Mechanic and Repair' started by clif, May 19, 2010.

  1. clif

    clif LawnSite Member
    Posts: 135

    No. Just change the throttle shaft, and if going to the 25hp, the oil cooler also.
     
  2. underPSI

    underPSI LawnSite Member
    Posts: 235

    What ^he said. And just for clarification the carb does not need to be changed either. There are no differences in the carbs between the 4 engines with the exception of a $28 throttle shaft which allows the throttle plate to open up a little bit more. The only available jets for the carb on these engines are for altitude adjustments, not for more power.
     
  3. underPSI

    underPSI LawnSite Member
    Posts: 235

    Clif, have you got your parts yet? Mine should be here middle of next week. I'm just eager to see how yours turns out first!
     
  4. clif

    clif LawnSite Member
    Posts: 135

    My parts are in, but they are at the hardware store where I ordered them. I've been working everyday since Tues. but I hope to be able to pick them up this Monday... Can't wait to see what kind of difference this conversion makes. When I get the parts and have time to tackle the project, I'll take several pictures and post them for everyone.
     
  5. kludgemonkey

    kludgemonkey LawnSite Member
    from LA
    Posts: 61


    Please do. I am eagerly watching this thread hoping to do the same to my 19 HP Kawasaki.
     
  6. tryingtomakeit

    tryingtomakeit LawnSite Member
    Posts: 40

    You can cut the throttle stop on the shaft where the linkage attaches back with a dremel with a cutoff disk too. Cut a little at a time until it opens 100%..
     
  7. clif

    clif LawnSite Member
    Posts: 135

    I bent mine out of the way, this thing was hard to access on my hustler mini z. The dealer had my rpm's set at 3550, the bottom end of the recommended range (3600rpm +/-50). I was able to attain 3750rpm, using a tachometer to check out where I was at. I played with the governor spring slightly as well. But when I put in the new throttle shaft I will likely cut back to around 3650rpm, I don't know now if the extra rpm's will hurt my engine, probably somewhat in the long term. I think the hydrostatic transmissions on these things are designed to peak at the 3600 rpm level, so you probably will only get a little more blade tip speed. I don't notice any forward speed difference, but it seems to handle the tall grass slightly better, but only very slightly.
     
  8. kludgemonkey

    kludgemonkey LawnSite Member
    from LA
    Posts: 61

    Question - Does putting this shaft in allow you to give the engine more throttle, thusly increasing the RPM to get more horse power; Or, does it give it more gas and air to create more horse power without increasing RPMs?
     
  9. clif

    clif LawnSite Member
    Posts: 135

    I think it just allows a little more fuel&air flow for more power, b/c think about it for second, all of these engines {19-25hp}are set at 3600 rpm from the dealer. The rpms are controlled by the governor. The shaft swap out should not have any effect on rpms, although I will measure mine before and after to verify this. And I will tune mine down from 3750 to 3650rpm, the highest recommended rpm according to the service manual.
    All that extra torque will translate to more cutting power, and enable you to cut taller/thicker grass while remaining (instead of slowing down due to engine bogging down) at your top speed. And hopefully it will be a little less likely you will have to re-cut some areas.
     
  10. clif

    clif LawnSite Member
    Posts: 135

    I have installed the oil cooler and throttle shaft in my mower, pictures have been taken, and I will upload some maybe tomorrow. Still have to put some things back together on the mower, didn't have time to finish. The oil cooler was simple, did my oil change since I had to remove the oil filter anyway. After removing the oil fitler and draining the oil, I unscrewed the threaded nipple that holds the filter, cleaned up the mounting area, and placed the oil cooler in it's spot and installed the extended nipple that holds the oil cooler. Then put in a new oil filter. Filled up with some full sythetic oil.

    The throttle shaft took a couple hours, had to remove a few parts from the mower, never could totally remove the carburetor (without removing the whole engine from the way it looks), but pulled it out enough to remove the old throttle shaft and install the new one. Will update with more info after I get all the parts back on my mower and am able to try it out. It should work great, the carb. barrel can now be fully opened as oppesed to only half way. The only difference in throttle valves is that the FH721V's doesn't have as much of a stop plate as the FH601v's, therefore, if you know what your'e doing you could simply grind off some of the restricter plate on your old valve. The pictures I will post will explain it better.
     

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