Briggs & Stratton 625 governor linkage question

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  #1  
Old 03-09-11, 10:03 PM
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Unhappy Briggs & Stratton 625 governor linkage question

OK, I think I've come up against my limit on this engine. Here are the details.

The engine wouldn't start, so I checked spark, it was good. Then I tried to start it with the throttle handle open and noticed that the throttle itself (on the carb) wasn't moving. If I engage the actual throttle on the carburetor the engine will start, but the throttle on the carburetor does not move when I depress the throttle on the handle of the lawnmower.

I took the engine apart to an extent and this is what I can tell you. The throttle cable is connected to a lever on the motor, and when depressed, releases the clutch on the flywheel and also releases what appears to be a spark inhibitor. Beyond that it doesn't seem connected to anything. There is a long metal handle that is not connected to this linkage, that connects to the throttle on the carb through a long piece of stiff wire. It appears as though when I depress the throttle bar this is supposed to open up the throttle on the carb, but this linkage does not work. I cannot tell if the link between the cable and the carb is inside the engine or if there is some piece missing that is supposed to connect these two things.

So, if this helps any, the disconnect is here:

Throttle bar > throttle cable > lever on motor that releases clutch on flywheel > ????? > Long bar > long stiff wire > throttle on carb.

Somewhere in that question mark area is a missing link. I hope it isn't inside the motor.

Thanks in advance.
 
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Old 03-10-11, 08:39 AM
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Post the engine numbers usually found stamped in the metal shroud above the spark plug or a tab by the muffler so we know what engine you have. The brake and stuff on the flywheel is for safety, It sounds like you may be missing the throttle spring, refer to the picture below for reference. Have a good one. Geo

 
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Old 03-10-11, 10:25 AM
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Thanks for the reply. No, the throttle spring is there. The throttle would operate except it does not appear to be affected by the throttle on the handle.
 
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Old 03-10-11, 10:53 AM
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As geo mentioned, you should post the numbers from the mower, in this case instead of the engine...
It sounds to me as though you are confusing the dead man bar with some throttle operation, which is not likely the case. While the cable may appear to go to the carb, it actually only opens the ground contact point to the coil to allow the coil to fire the plug.
If you do have a separate throttle control, you should have two cables. If not, which many mowers do not, then the throttle is set to run at full speed, and essentially, only allows on/off via the safety bar.
If you do have a separate throttle control, movement of it while the engine is not running will not have a visible effect on the carb. It actually changes the tension on the spring to the governor which is inside the engine and functions by the engine spinning.

 
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Old 03-10-11, 11:06 AM
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Hopefully this helps. This is a B&S 625 (6 hp push mower engine)
 
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Old 03-10-11, 11:27 AM
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Originally Posted by BFHFixit View Post
As geo mentioned, you should post the numbers from the mower, in this case instead of the engine...
It sounds to me as though you are confusing the dead man bar with some throttle operation, which is not likely the case. While the cable may appear to go to the carb, it actually only opens the ground contact point to the coil to allow the coil to fire the plug.
If you do have a separate throttle control, you should have two cables. If not, which many mowers do not, then the throttle is set to run at full speed, and essentially, only allows on/off via the safety bar.
If you do have a separate throttle control, movement of it while the engine is not running will not have a visible effect on the carb. It actually changes the tension on the spring to the governor which is inside the engine and functions by the engine spinning.

Thanks, you're right, it's not a throttle, it's just a dead man bar.

So, at this point, what I can say is if I engage the throttle on the carb, the mower will start. If not, it won't.
 
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Old 03-10-11, 12:34 PM
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Find Your Model Number | Generators & Pressure Washers | Briggs & Stratton

Help on locating your engine model number, also if you can inform us of at least the make of the mower, can also help you find that info...which is of the utmost help to us, in order to provide you with accurate assistance.
 
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Old 03-10-11, 12:40 PM
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From you photos, I don't see anything off hand wrong...
Your reference to the metal arm, is the governor arm and is attached to the governor which is internal.
Any chance during your
I took the engine apart to an extent
you loosened or changed the position of this arm on the shaft?
 
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Old 03-10-11, 05:50 PM
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No, I didn't adjust this at all.

The mower is a Yard Machines from about 2003, rear discharge. The engine is a 6hp B&S, they say it the 625 series. The label says "family: 2bsxs 1901vh" on the side.
 
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Old 03-10-11, 06:20 PM
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From your pic it looks as though the linkage could be bent as if it were run under a bush or something, try bending the tab(the circle the spring is hooked into) forward so as to put some tension on the spring, don't over do it. Have a good one. Geo
 
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Old 03-31-11, 10:12 AM
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The throttle moves freely if I move it myself. What I was saying is the governor linkage doesn't move, so the throttle doesn't move unless I manually move it.
 
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