B&S engine governor problem

Discussion in 'Shop Talk' started by mary,tx, Sep 23, 2004.

  1. mary,tx

    mary,tx Well-Known Member Supporter

    Messages:
    4,628
    Joined:
    Dec 4, 2002
    I was having problems with my B&S 2 cyl engine for my riding mower and had previously posted the problem. Running rough, burning rich, etc. I cleaned the air filter, replaced plugs, fuel filter, needle valve, cleaned carb (twice), adjusted the tab on the float, etc.

    After putting the whole thing back together after disassembling the carb for the second time, I still had the problem. After starting, then engine ran fine, that is for awhile until I put it in gear (under load).

    I discovered the problem was NOT the carb. I noticed the throttle on the carb was pushed wide open, but the engine was rough and giving off black smoke. Pushing on the governor lever a few times cleaned up the problem--the engine settled into running great. That is of course, until put under load. Again messing with the governer lever (that connects to the throttle lever on the carb) while the engine was running brought everything back into line. It seems like it wants to push the throttle wide open and then too much fuel causes it to burn rich and I guess since it is not reving up to speed due to the (rich rough running) it keeps the throttle wide open.

    I know nothing on how the governor works other than it is between the throttle control lever on the dash and the throttle lever on the carb and that messing with it makes the engine run smoothly again.

    What gives and what do I do now?

    Thanks,
    Dale (dh of mary, tx)
     
  2. moopups

    moopups In Remembrance

    Messages:
    7,102
    Joined:
    May 12, 2002
    Location:
    In beautiful downtown Sticks, near Belleview, Fl.
    Was the linkage disconnected when you took off the carb? If yes then look for wear marks on the adjustment holes, is everything in the right place? Also look for missing or broken tension springs. There is a possiability that the clamping portion of the control arm changed its position when you took off the carb. Short of gaining a manual I can say nothing else, I am not familiar with your paticular engine. One possiability is to set the arm clamp in the middle of the travel distance and try it, make adjustments from there. Best is to wait for a correct answer if you have time.
     

  3. mary,tx

    mary,tx Well-Known Member Supporter

    Messages:
    4,628
    Joined:
    Dec 4, 2002
    moopups,
    Everything moves smoothly and has spring tension. It appears that springs, linkage, etc. are all ok. I still have my original problem. It's like the governor has a mind of its own.
    Dale

     
  4. insanity

    insanity Well-Known Member

    Messages:
    890
    Joined:
    Aug 22, 2004
    Location:
    Clarksville TN.
    How dirty is the cover? I just took the cover off my mother laws mower a few weeks ago.The little flap that pushes back and forth under the cover was not able to move properly because of dirt cling to it.This part opens/closes the Governor.Might take a look.

    You also have the same engine that i have on my rider.Also a few weeks ago i washed it off Good! got the coils/plug wires wet.It ran fine until i put it under a load then you could tell something was wrong.I cant recall it smoking,but it did stumble and miss fairly bad.I let it dry out over, night next day it was fine.Could your problem be do to one cylinder not fireing?
     
  5. golfball

    golfball Member

    Messages:
    10
    Joined:
    Mar 16, 2004
    Location:
    Arkansas
    What year model is the engine? I would almost venture to say your problem is in the magneto or electrical charging system.
     
  6. mary,tx

    mary,tx Well-Known Member Supporter

    Messages:
    4,628
    Joined:
    Dec 4, 2002
    The date code shows that it is a 1997 model engine
    Model: 42A707 Type: 1238-01 Code: 9701035B

    How do I determine what is the problem?
    Thanks,
    Dale (dh of mary, tx)


     
  7. golfball

    golfball Member

    Messages:
    10
    Joined:
    Mar 16, 2004
    Location:
    Arkansas
    The reason I postulated the magneto or the charging system is because that is what it sounds like to me. First things first though, the wire from the magneto where it emerges on the engine to the outside should be checked for brittleness, or cracks. Chances are that you got your engine hot more than once and the excessive heat will cause the wiring to turn brittle and crack in most cases.

    You may also want to remove the safety cover from the top of your engine (or the side) and lightly sand the edges of the magneto to remove any rust that may be covering the magnet area. Rust builds up because of outside moisture in the air (high humidity) and leaving the lawnmower out in the rain and other elements.

    Through cracks in the wiring, you will lose power due to "arc-ing" of the spark or fire. You can find this by inspecting any area where the wires are close to heat sources such as the exhaust area, or of the engine block itself.

    According to what I read, you thought it was a governor problem. Well, you are mostly right because the real problem is the way the fuel burns.

    An engine needs three things to run. Fuel, Air and Fire.

    Apparently you went completely through the fuel system and you have a clean air filter, so it has to be a "Fire" problem.

    From my own experience, I have had a similar problem like yours where my motor worked fine at an idle, but when placed under load, it slogged through short grass and died in the tall stuff. A friend told me about the wiring aspect and I checked that. My wiring was okay, but when I looked at the magneto, it was covered with rust. After I sanded off the sides of the magneto with store bought sand paper, medium grit, it works like new.

    Basically, when you go completely through your fuel and fuel delivery system and find nothing wrong, there IS nothing wrong with your fuel system. It has to be an Air problem, which does not seem to be the case here, so that leaves the "Fire" aspect. I hope this helps you.
     
  8. mary,tx

    mary,tx Well-Known Member Supporter

    Messages:
    4,628
    Joined:
    Dec 4, 2002
    Thanks golfball,
    I will look into this during the week. Sunday is a day of rest here (except the chores that need to be done such as feeding, watering, and milking). I also noticed on another web side that governors require airflow from the engine to operate and I will also check for proper airflow to the govenor.
    Thanks,
    Dale (dh of mary,tx)