John Deere 737 757 717 Kawasaki FH601D, FH641D, FH680D upgrade to 25HP, FH721D. Part 1



Quick directions on how to increase the horsepower on your 19, 21, or 23HP FH601, FH641, or FH680D engine to 25HP. On the 25HP engine, there is also an oil cooler that needs to be added to help keep the oil cool.

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6 thoughts on “John Deere 737 757 717 Kawasaki FH601D, FH641D, FH680D upgrade to 25HP, FH721D. Part 1

  1. OK gotcha… well it does do both, so I guess it's good… really didn't do much till I adjusted the governor down on the slots. I actually think you could probably gain a hp just by doing that!… anyway thanks and thanks for the video… I was afraid to grind till I seen it… but I thought well it's gonna be 30. bucks either way… lol

  2. I know that! I was just describing where the throttle shaft stop is on the carb! what I'm saying is when the engine is running the throttle stop never hits it so why make the change?

  3. I did the adjustment on the throttle stop, but I'm not convinced this will add any hp, because the governor keeps the throttle shaft stop well away from the carb casting stop with the idle screw in it. And yes…..I've adjusted the governor (both ways) and it still will not hit the stop.
    Am I missing something here?

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