# Briggs & Stratton Stalls at High Throttle



## John Montalbano (May 28, 2011)

Briggs & Stratton 28u707 OHV engine stalls at high throttle. I have already replaced plug, fuel and air filters, adjusted valves. Still worked only at mid speed for a few weeks and then was hard to start yesterday. I cleaned the carb this morning and now I see that the choke closes but the throttle does not open as I try to increase throttle from the speed lever. If I force the throttle butterfly manually, the engine goes up to speed nicely. I am not sure if this was the problem to begin with or if I assembled the linkage incorrectly.

Can someone confirm that the thin spring that wraps around the throttle linkage connects to the hole on the throttle butterfly that is next to the throttle linkage. If yes, I don't understand how it does anything. If no, where does it attach?

Am I correct that the speed lever chokes the carb and then the governor reacts by opening the throttle? Otherwised I do not see how the throttle cable on this engine cause the throttle to open.


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## usmcgrunt (Sep 16, 2007)

Here is a link to the service manual which has diagrams for the throttle linkage.Hope this helps.

http://www.mymowerparts.com/pdf/Bri...781 Single Cylinder OHV BRIGGS & STRATTON.pdf


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## John Montalbano (May 28, 2011)

Perfect. Thank you very much. I see that it has what I need and I will take a closer look. You made my day.


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## usmcgrunt (Sep 16, 2007)

Your welcome,hope the repair goes well.


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## John Montalbano (May 28, 2011)

Now I know that I have the throttle spring correct. 

When the engine is off, the throttle is wide open as it should be. When the engine starts, the throttle closes as it should. So the governor is not completely inoperable. 

As I increase the throttle lever, the choke eventually starts to close, but the throttle never opens. Do you think I am on the right track to think this the governor mechanism in the crankcase?


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## usmcgrunt (Sep 16, 2007)

Here is a link to the static govenor adjustment courtesy of 30yearTech.

http://www.hobbytalk.com/bbs1/showthread.php?t=221963&highlight=governor+adjustment


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## John Montalbano (May 28, 2011)

I had already done that and found it OK to begin with. Am I correct that there is no direct linkage between my throttle lever cable and the throttle butterfly on this 28u707? I just don't see that there is. Is the throttle opened indirectly by the governor as the choke "closes" at higher throttle?

Also, I am wondering now why the choke closes as I increase throttle? Should it not be opening?

Meanwhile, I increased the idle with the idle adjust and the mower ran fine for a few hours today. I'll give it another look on Monday.


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