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B/S 44s977 Power Issue

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RetiredMarine
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2025/06/02 13:37:22 (permalink)
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B/S 44s977 Power Issue

Recently swapped a Kawasaki fr691v engine for a Briggs and Stratton 44s977. The B&S is new but doesn't "sound/feel" like its as powerful even though it has slightly more horsepower. The Kawasaki has a separate throttle and choke cable. The B/S only has a throttle cable. I push it all the way forward to choke and start and then back it off to about 3/4 for full power. However even at this setting it doesn't feel/sound as strong as the Kawasaki did. I can manually pull down the governor linkage and the engine reves higher. I'm wondering if the govner isn't set properly or if that the B/S engine is just a more efficient engine. Thoughts?
 
Chris
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    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/02 15:41:24 (permalink)
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    Look and make sure the choke is opening fully when your at full throttle.
     
    You can also put a tach on/ near the spark plug and check for 3,600 RPMs (Max, loaded running RPM's)
     
    .

    Scott
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    Re: B/S 44s977 Power Issue 2025/06/02 16:08:31 (permalink)
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    The choke if fully open when it reaches operating temperature - it's all the way up.  However the arm attached to the governor can still be moved reving the engine.  
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    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/02 16:12:05 (permalink)
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    The arm to the governor (movement) is as it should be. 
     
    As RPMs drop, governor raises the RPMs-
     
    Likewise, RPMs too high, the governor will lower them..
     
    .
     

    Scott
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    Re: B/S 44s977 Power Issue 2025/06/02 16:14:06 (permalink)
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    I agree the governer is working properly, I guess my question is it set properly at full power or should it be increased?
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    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/02 16:51:50 (permalink)
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    RetiredMarine
    I agree the governer is working properly, I guess my question is it set properly at full power or should it be increased?   

     
    To know if it's at full power, a tachometer is needed.   You can get an inexpensive one on Flea Bay.
    Most engines, max RPM's is 3,600.  Only a tachometer will give you exact full power speed of the engine.
    Confirm with your owners manual/ manufacturer, the max RPM's.  
     
    And yes, you can adjust the RPMs higher (or lower).  There's (in the larger engines) usually a phillips head screw 
    that when turned can raise or lower the speed.  Usually, the TIGHTER the spring tension, the higher the RPM's. 
     
     
    **It should be noted, that smaller machines, (some walk behind mowers, 5-7 torque), the US government made manufacturers reduce max RPMs to 3,400..  This is to make the machine "safer" should it hit an object (  ???  ).  The engine itself CAN run at 3,600...
     
     
    .

    Scott
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    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/02 16:53:53 (permalink)
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    https://www.insidetheyard.com/briggs-and-stratton-rpm-chart/ 
     
     
    .

    Scott
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    Re: B/S 44s977 Power Issue 2025/06/09 11:35:00 (permalink)
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    SRTsFZ6
    https://www.insidetheyard.com/briggs-and-stratton-rpm-chart/ 
     
     Ordered a tachometer from Amazon, it reads 2730 rpm.  I don't see anything in the article you posted about a model 44S977 which is what is stamped on my motor.  Thoughts?
     
    Chris




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    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/09 13:10:07 (permalink)
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    I'm seeing 3,300 as max RPMs:
     
    https://www.kohler-engine-parts.opeengines.com/briggs-stratton-replacement-engines-briggs-vertical-shaft-engines-c-1100_1143_1224/briggs-stratton-engine-44s9770033g1-25-hp-1-18-724cc-p-52048 
     
    So you can adjust the RPMs up a bit W/O issue.
     
     
    post edited by SRTsFZ6 - 2025/06/09 13:11:20

    Scott
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    RetiredMarine
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    Re: B/S 44s977 Power Issue 2025/06/09 13:49:24 (permalink)
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    It seems to be cutting just fine and the lower rpms mean a longer engine life, and I assume if the mower demands more power the governor will deliver. I think I'll run it like this for a while unless others have information that changes my mind. In that event would I increase the rpms by adjusting the governor?
    Quote  #10
    SRTsFZ6
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    Re: B/S 44s977 Power Issue 2025/06/09 14:10:30 (permalink)
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    The governor will bring back up the RPMs to what it normally runs should the engine
    bog down.   It won't automatically raise the rev's say 500 RPMs ABOVE your normal setting..
    It may under much load, open the throttle to fully WIDE OPEN  BUT only to your max RPMs as previously set..
     
    Now, there should be (usually is) a phillips head screw (kinda small), that you would turn to adjust
    spring pressure on the governor assembly should you need to raise RPMs (at WOT).  
     
    DO NOT adjust the arm / shaft / etc of the governor to achieve higher RPMs, that won't achieve
    what your trying to do and just make new problems to resolve.....
     
    And I agree, if the mowers cutting fine with the lower RPMs, (W/O bogging, too much load), 
    I'd leave it as is.  You likely have enough HPs as is and the engine will like you better for it..
     
    .
    post edited by SRTsFZ6 - 2025/06/09 14:14:42

    Scott
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    RetiredMarine
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    Re: B/S 44s977 Power Issue 2025/06/10 07:19:02 (permalink)
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    Thanks!
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