19 HP Kawasaki FH601V engine hp upgrade?

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

  1. dnrsslr

    dnrsslr LawnSite Member
    from Ohio
    Posts: 75

    Hmmm... Looks like I was WRONG! Doing a little more research... My engine is a FH601V-CS13. When I compare the FH680V-DS22 to the FH680V-CS13, I see the DS22 has a round bowl at the bottom of the carburetor and a circular float. The CS13 has a rectangle bowl and the float is butterfly shape. And the throttle shafts seem to have different part numbers and prices. I guess if we just grind the throttle we don't need figure out which parts to buy! I'm currently waiting for "my guy" to get back from vacation so he can grind this for me.

    Maybe the FS15-R means "must buy parts from John Deere"! :)

    Incidentally, I bought the oil cooler and installed that without a whole of effort! If nothing else, it should run a little cooler.
  2. cbegap

    cbegap LawnSite Member
    Posts: 141

    I just mowed the entire weekend after this upgrade. Worth every penny. You can hear the engine note deepen as the governor opens up going through the tall grass. It made for less clumping so I didn't have to run back over stuff. Has to be the cheapest HP upgrade around even with the carb shaft being a little pricey for what it is. Whatever, love it love it! Kudos to whoever took the time to give this idea momentum. Just remember to do like piston slapper said and adjust the governor. Don't confuse the high idle adjustment with adjusting the gov. Like someone before said, it is only doing it's job under load so just sitting there running the butterflies are barely open.
  3. dnrsslr

    dnrsslr LawnSite Member
    from Ohio
    Posts: 75

    Just go my tractor back last night. The guy used a tin snips to cut the part you usually grind but they couldn't cut clear through. So he had to bend it back and forth with a pliers until it broke. He showed me before and after pictures of the throttle plate; WOW! Before was less than 1/4 open and now it's nearly wide open. He also "bored" out the jets a wee little bit. I mowed a little bit but not enough to have any idea of power yet. I'll keep you all updated.
  4. dnrsslr

    dnrsslr LawnSite Member
    from Ohio
    Posts: 75

    I finally mowed my lawn last night. I don't have any real objective evidence. But, it definitely seemed to have more power. I sometimes mow with double blades but, in the past, they seemed to take almost too much power for my tractor. Last night, the tractor had no problem running double blades! I would say a definite success!!!!
  5. duckwood

    duckwood LawnSite Member
    Posts: 10


    Can you elaborate if the governor needs adjusting if you install a new throttle shaft (in this case 23 HP, original is 19), versus grinding down the original?

    I do not see any instructions for adjusting the governor in the service manual? How do I adjust it?

    Thanks very much!
  6. finneylawns

    finneylawns LawnSite Member
    Posts: 59

    When I did it on mine, I did not do anything to the governor. Just pull the old shaft out and put the new shaft in. You will see the difference in the butterflies. The engine will remain at the same RPM, and will remain near the same RPM in tall grass for a longer time. IE able to cut through the occasional tall/thick grass without it bogging down.

    For some reason I am not able to get the pictures display correctly, but you get the idea.

    The first picture below is of the old shaft at WOT.

    Second picture is of the nes shaft at WOT.

    You can see the difference in the butterflies. I was skeptical, even after starting the machine up. I did not see or hear any difference. It was not until I was cutting some thick grass that I was able to see and hear the difference.

    Also improved my gas consumption from 0.5 Hours per Gallon to .9 Hours per gallon, this is with a mulch kit installed on a JD 910A 48" deck. Don't ask me how that happened, other than the mower was greatly under power. My original gallon per hour was 0.7 without the mulch kit. So with that math my eleven gallon tank cost $40 to $45 to fill. (93 octane). So being able to mow nearly twice as long on a tank, and the part costing $25 it paid for itself in the first tank.

    Old Shaft WOT.jpg

    New Shaft WOT.jpg
  7. cbegap

    cbegap LawnSite Member
    Posts: 141


    IMHO I don't think you are realizing the full benefit of the upgrade unless you adjust the governor. One side of the shaft is to touch on the idle adjustment screw, and the other is a fixed point that stops the shaft from rotating. You are changing the non-adjustable side with a new shaft or cutting. There are two things that limit the opening of the butterflies. The first is the shaft that you can either replace or trim/cut so that the shaft rotates more allowing the butterflies to open more (you just fixed this issue). The second is the governor. The governor linkage etc. has a fixed length shaft coming off of it that goes up to the carb shaft you just replaced/cut. My governor was set in relation to the old shaft. So at max load, the governor would open the butterflies to the old max position (barely open, 19HP). If the governor opens to the same old spot, that is now not far enough because you have changed the stopping point of where the shaft needs to travel. I guess you could get lucky, but I had to adjust mine. There is no adjustment on the little itty bitty shaft between the governor arm and the carb. There is no adjustment on the carb, so that leaves the governor arm position in relation to the shaft coming out of the block. With everything reassembled, I loosened the nut that tightens the governor arm to the shaft coming out of the block just enough so that it would move on the shaft. Then I pushed up on the arm, which in turn slid on the shaft counter clockwise until the rod pushed the shaft to the new stop position. I tightened everything up and that was that. Fast RPMs are adjusted by loosening the two screws and moving the entire assembly up and down. Low idle has the adjusting screw that I get at through the air cleaner mounting plate. You can make the shaft open more, increasing fast rpm, by pushing the plate up, which pulls up on the spring that hooks to the middle of the arm allowing faster RPM at WOT. If at wide open there is no more travel in the arm, the butterflies will not open all the way and not increase the air/fuel quantities and not improve HP. This is at least the way I understand it. I am not a certified mechanic or anything so there is my disclaimer. YMMV. My experience is that my mower doesn’t sound different, go any faster or do anything different until I get into some deep thick grass and then you hear it buckle down and really open up. Before tall grass would start to come out in balls and then eventually puke (when wet). Now it comes out in a solid sheet of grass. I can still go too fast and outpace what the deck can handle which will leave a bad cut, but the motor doesn’t bog down and loose the RPMs and the discharge is more constant. I have yet to have to double cut a yard like I have in the past.

    You may be realizing better fuel consumption because you changed your high idle RPM. If you didn’t set it as high this time around, you get better economy. Most companies ship mowers around the 3300-3400 RPMs for economy and longevity. 3600 is a popular number but increases fuel consumption. Otherwise it is counter intuitive that you would be introducing more air and fuel and have fuel consumption decrease.
    Last edited: May 9, 2013
  8. duckwood

    duckwood LawnSite Member
    Posts: 10

    Well I finally did this today as well. At first I had the same problem that Cliff had long ago, the engine was just running at full throttle with no throttle control. I thought I would share this for anyone else who experiences the same issue. It took a little bit to figure this out, but it was because I had improperly adjusted the governor. The instructions say to loosen the nut, rotate the governor arm counter clockwise, and rotate the shaft counter clockwise. Then tighten the nut. Well I thought I had rotated the shaft counterclockwise all the way, but it turns out I did not. Get a small phillips screwdriver and put it in the hole in the governor shaft. Use this to rotate the shaft all the way. It goes further than what you can get using your fingers on the shaft alone. Then tighten the nut, and you should be good to go.

    Thanks all who have done this before for the tidbits of information that helped me.
  9. User Name Taken

    User Name Taken LawnSite Member
    Posts: 92

    Well shoot, I was under the impression when I did this I only had to adjust a modded shaft governor. Going from a 23 to a 25 I felt it was more powerful when loaded but I guess I need to check this again. It's been running good for a couple years now.
  10. stonebridge

    stonebridge LawnSite Senior Member
    Posts: 867

    hows everyones upgrades doing i want to do it to my 23hp kaw to a 25hp
    seems all i need is a oil cooler and shave down the throttle stop and adjust the governor
    is that all?

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