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Turfco Aerator -- 3.5 Briggs IDLE ADJUSTMENT

Discussion in 'Mechanic and Repair' started by jlbf0786, Sep 27, 2013.

  1. jlbf0786

    jlbf0786 LawnSite Senior Member
    Male, from Charlotte, NC
    Messages: 616

    I need to lower the engine RPM's on this 3.5hp Briggs I/C, I just bought the machine yesterday and I haven't been able to use it due to it revving up too high upon cranking it.
    I'm not sure if it's just me or if it's actually revving up past 3600 (engine spec from B&S site)

    I've lost my tachometer and don't have a way to check the actual RPM's

    So just to be on the safe side I want to lower them, can anyone give me a quick HOW-TO on this?

    Model Type Code
    93452 0049 05 94050903

  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    One end of the governor spring hooks to the governor arm, The other end hooks to a tang/tab on the back of the throttle control assembly.

    Bend this tang/tab to reduce the pull on the governor spring while the throttle is set to fast position, This will lower the high speed RPM's......
  3. jlbf0786

    jlbf0786 LawnSite Senior Member
    Male, from Charlotte, NC
    Messages: 616

    after i seen your reply i went back out to take a look at it.

    *This is the best description I can give, so bare with me:
    I noticed that the governor arm was bent outward and the linkage was bent as well. I straightened them both back to where they should be. I tried cranking it up and it was trying to start but it was just not firing up (acting like the RPM's were then too low)
    but all of a sudden the thing fired up and REVVED way up. I shut it off before I could screw it up anymore.

    Is it possible that the internal governor is just shot? and if so, what would be the best course of action? -- I can probably buy another engine, cheaper and less-time consuming than having this one repaired. Right?
  4. jlbf0786

    jlbf0786 LawnSite Senior Member
    Male, from Charlotte, NC
    Messages: 616


    The RPM's skyrocket as soon as you start it up. I have the throttle set on the lowest point.

  5. tigerepairdotcom

    tigerepairdotcom LawnSite Senior Member
    Messages: 330

    I believe that you may have a post carb an air leak. Pulling false air after the carb is likely the culprit to a high rev non controllable. Someone is likely to make governer spring adjustments rather than fix carb issuses
  6. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    That may be true on 2 cycle engines but a four cycle engine will NOT rev to the moon from any air leak or carb issue other than a throttle shaft stuck wide open......


    Static governor adjustment;

    Grab the governor arm and move it to where the carb throttle shaft is in the wide open position, Pay attention to the shaft the arm is attached to and which direction it rotates when moving the arm to wide open.

    Loosen the pinch screw on the arm, while holding the arm with the carb wide open rotate the shaft the same direction until it stops. Hole a slight pressure on the shaft and arm then re-tighten the pinch screw on the arm.

    See if this solves the over rev.......
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,329

    Not gonna happen on a 4 stroke engine...a single cylinder engine would prolly fall on it's face with a bad intake leak...
    Make sure the butterfly in the carb is still attached....if it is loose or missing the engine will hit the high notes...
  8. jlbf0786

    jlbf0786 LawnSite Senior Member
    Male, from Charlotte, NC
    Messages: 616

    Can I replace this 3.5 Briggs I/C with one of these 212cc 6.5HP Harbor Freight Engines?
    I can get one of them for $89 before tax. I can swap it out easier and probably less expensively than waiting on someone in the repair shop to look at it.

    I need this thing up and running before mid-week this coming week.

    Here's the specs on the engine from Harbor Freight:

    6.5 HP (212cc) OHV Horizontal Shaft Gas Engine
    SKU 69730
    Application pressure washers, cement mixers, compressors, mowers, log splitters, vacuums, tillers, water pumps, chipper/shredders, generators, blowers
    Certification EPA
    Diameter 70 mm
    Engine displacement (cc) 212cc
    Horsepower (hp) 6.5
    Maximum speed (rpm) 3600 RPM
    Maximum Torque (ft. - lbs.) 8.1 ft. lbs. @ 2500 RPM
    Mounting pattern 162mm L x 75.5mm W - 80.5mm W (6.40" L x 2.95" W - 3.17" W )
    Shaft output Counterclockwise
    Shaft rotation direction Counter clockwise
    Sound rating (dB) 104 dB
    Start type Recoil
    Product Height 14 in.
    Product Length 12-1/2 in.
    Product Weight 37.5 lbs. / 17 kg
    Product Width 14-1/2 in.
    Shaft length (in.) 2.43" / 61.7 mm
    Stroke length (in.) 55 mm
    Warranty 90 Day
  9. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If the crank is the same size go fer it.......
  10. jlbf0786

    jlbf0786 LawnSite Senior Member
    Male, from Charlotte, NC
    Messages: 616


    I went and bought a 212 cc (6.5hp) engine from Harbor Freight. I came back home and started unbolting the Briggs from the Turfco aerator frame, got the 4 bolts out of the engine to frame. Now, how does the gear reduction box come off ?
    Do i need to drain the gear box oil 1st or can it stay full and not have to be broken open to remove from the engine's shaft?

    I can't remember how i done this years ago, its the same configuration on all of them..

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