playing with the governor

Discussion in 'Lawn Mowing' started by yorkpaddy, May 1, 2001.

  1. yorkpaddy

    yorkpaddy LawnSite Member
    Posts: 137

    I run a toro 36, with a 12.5 kawasaki. I have an hour/tach on it. Sometimes when i cut heavy grass it bogs down. at fast idle it was 3300, blades engaged it was 3200, and it would bog down to 2900-3000 in heavy stuff. Well I tried to adjust the governor, super frustrating. When I first undid the screw on the arm from inside the engine, it would rev right up to 4500, probably higher if i hadn't shut it down. I finally figured out how to just nudge it up a little, and then tighten the screw. I got 3500 idle, 3400 engagement, then tried to tweak it a little more, and it went crazy fast again. So I brought it down again, and left it at 3400/3350. I want to get it to 3700-4000 idle and 3600-3800 blades engaged. I'm not to concered about engine life cause i only put 170 hours on it last year, and when it breaks i'll throw a 14 hp kawasaki on it. any tips on how to better adjust the linkage
  2. MikeLT1Z28

    MikeLT1Z28 LawnSite Bronze Member
    Posts: 1,732

    i wouldn't think it would bog unless you are running the deck at a really low setting. how high/thick is the grass and what deck height are you cutting at?
  3. TLS

    TLS LawnSite Fanatic
    Posts: 7,937

    Kawi's rpm's are adjusted by loosening the throttle linkage plate assembly (where the cables meet the linkage) and adjusting it front or back. Its rather simple and precise, not like you are describing. You must be doing something wrong. I have my 14/48 set at 3700 free/ 3600 +/- with blades engaged. 3300 is too slow.

  4. yorkpaddy

    yorkpaddy LawnSite Member
    Posts: 137

    how I would adjust is I'd.
    1. losen the screw
    2. torque the shaft back and Try to hold it there
    3. try to position the arm in a position that relative to the shaft,
    4. keeping everything in the same orientation tighten things up
  5. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    Part of your problem is you're trying to adjust RPMs using the govenor. This is not what the govenor is for. On these small engines all the govenor does is open the throttle plate when it senses a loss in RPMs. Without it most engines would die as soon as they encountered heavy grass. It's kinda like when you encounter a hill when you're driving your truck and you press down on the gas to maintain speed when you're going up the hill.

    There is a safety issue involved here too. It is blade tip speed. Any rpm increase above 3600 with the blades rotating could increase the blade tip speed beyond the legal limit of 19,000 fpm. A unbalanced blade rotating faster than that could set up harmonics that could shatter the blade sending shards and pieces of blade flying around at well over 200 mph.

    Just follow Dixie 1's advice on how to increase RPMs and stay around 3600 with the blades engaged.
  6. yorkpaddy

    yorkpaddy LawnSite Member
    Posts: 137

    thats another reason i want to increase the rpms, to increase the blade tip speed. Since i'm a solo operator, OSHA doesn't scare me to much. And the harmonics thing, you'd be as likely to get a harmonic at 2700 rpm as 4000. Now extra vibrations yes, and extra spindle wear yes. But harmonics no
  7. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    I hope your insurance is paid up. The harmonics come from the vibrations by the way. You would not likely hear or feel the one that breaks a blade.
  8. Alan

    Alan Member
    Posts: 1,185

    From what i see, the throttle only moves teh governor linkage on most engines and the governor holds the RPM both at idle and load. In an idealw orld there would be no RPM drop until the engine was at maximum load at full throttle (as set by the governor). The end result of all that is that you DO need to adjust the governor to make changes in full throttle speed.

    As far as blade breakage I tend to discredit the harmonic effect as a factor unless you got really wild on RPM. In I don't know how many hours of mower operation I have seen only one blade break and that was because I had welded two blades into a cross to use for bagging leaves. Picked up a big stone and it snapped a blade at the weld. Even running full tilt all it did was drop the pieces on the ground, no big dents in the deck or anything. Has anyone here seen a blade break during use. I am talking seen it themselves, NOT knows somebody who knows somebody who had a buddy who broke one. It's like airbags deploying on plow trucks, everybody has heard of it happening but nobody has had it happen to them.
  9. KirbysLawn

    KirbysLawn Millenium Member
    Posts: 3,486

    Sounds this is a common sense & safety issue. OSHA, your right, they would probably never know. However if a blade shatters and kills you or injures/kills any by standers, well it will be an issue then.

    Up the insurance policy, the tool man is going to work.
  10. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    The proper, factory recommended adjustment for fast idle RPMs is as Dixie 1 described above. Go buy the manual, I did.


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