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A Briggs Engine Model 331877-1371-B1 was running fine. It was shut down to refuel and upon start up it revved very high and lowering the the throttle produced very little change. With the throttle control in low, I can manually push the butterfly plate/linkage against the idle adjustment screw to produce the low end rpm's, but as soon as I let go it takes off to high rpm's. I do not see any parts missing in reference to the parts manual. I loosened the governor arm from the shaft and it seems to make little difference to where as the adjustment of the arm position is concerning at the rpm's. Also the governor shaft seems to move a total 30 to 45 degrees. Anything else to check before I decide it is an internal problem with the governor?

Shade Tree Mech said:

A Briggs Engine Model 331877-1371-B1 was running fine. It was shut down to refuel and upon start up it revved very high and lowering the the throttle produced very little change. With the throttle control in low, I can manually push the butterfly plate/linkage against the idle adjustment screw to produce the low end rpm's, but as soon as I let go it takes off to high rpm's. I do not see any parts missing in reference to the parts manual. I loosened the governor arm from the shaft and it seems to make little difference to where as the adjustment of the arm position is concerning at the rpm's. Also the governor shaft seems to move a total 30 to 45 degrees. Anything else to check before I decide it is an internal problem with the governor?

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Check to see if you're governor spring is not in a bind.

Since you have loosen the governor shaft. First do a static governor adjustment.

Now with it being a 330000 series with the 793880 camshaft the ACR may have failed and took out the oil slinger/governor assembly. I have replaced two of those oil slingers/governor this year because of a failed ACR.

PTmowerMech said:

Check to see if you're governor spring is not in a bind.

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No, I checked. It is extended/vertical when the throttle is open/high and relaxed/horizontal when the throttle is low, but the butterfly linkage plate isn't against the idle adj. screw. It never rests against it on it's own. I can push it against the idle adj. set screw with no problem, and the engine's rpm go down as they should, but as soon as I let go the engine's rpm go way high. That tells me it isn't a carb. issue, agreed? The carb. reacts when told. Also, when I push the butterfly linkage plate against the idle adj. screw; it looks like the governor spring just starts to extend the ever slightest bit horizontally. The best result being if I hold the governor arm full throttle and turn the governor shaft full clockwise even though the engine 's rpm is way too high. I don't need an actual rpm gauge to know if I let that thing run long it is going to scatter.

StarTech said:

Since you have loosen the governor shaft. First do a static governor adjustment.

Now with it being a 330000 series with the 793880 camshaft the ACR may have failed and took out the oil slinger/governor assembly. I have replaced two of those oil slingers/governor this year because of a failed ACR.

Click to expand...

By static governor adjustment, do you mean with an rpm gauge and start bending linkage metal? I believe I did a governor adjustment, but I am not sure of what a static adjustment is, sorry.

FYI: The engine starts up on every attempt, even if I hold the butterfly linkage at low throttle.

Static Adjustment

1. Loosen screw holding governor lever to governor bell crank.

2. Rotate throttle linkage from idle position to wide open throttle. Note direction of
rotation of the governor arm attached to the throttle linkage.

3. While holding linkage at wide open throttle, use the appropriate tool to rotate
the governor shaft until it stops in the direction noted in Step 2.

4. Tighten screw holding governor lever to governor crank to spec.

5. Before starting engine, manually actuate throttle linkage to check for binding.

StarTech said:

Static Adjustment

1. Loosen screw holding governor lever to governor bell crank.

2. Rotate throttle linkage from idle position to wide open throttle. Note direction of
rotation of the governor arm attached to the throttle linkage.

3. While holding linkage at wide open throttle, use the appropriate tool to rotate
the governor shaft until it stops in the direction noted in Step 2.

4. Tighten screw holding governor lever to governor crank to spec.

5. Before starting engine, manually actuate throttle linkage to check for binding.

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That is what I did. Full throttle is CW on the governor linkage arm and I turned the governor shaft CW and tightened it down.

Thanks for the replies. Are we all thinking the same thing? Drop the sump and see what's broke.

Shade Tree Mech said:

Thanks for the replies. Are we all thinking the same thing? Drop the sump and see what's broke.

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To me that would be the next step.

Shade Tree Mech said:

Thanks for the replies. Are we all thinking the same thing? Drop the sump and see what's broke.

Click to expand...

The governor is what SLOWS the engine so if an engine will not run slowly then the governor has failed.
The failure can be as simple as the shaft coming lose or as complex as the governor requiring replacement.

Also, could I be missing a third spring or linkage that I am not seeing in pictures or schematics? I am not understanding how it knows to back down the throttle from high to low. I haven’t been convinced that I’m not missing something.

The springs hold the throttle open
The governor PUSHES it closed

Shade Tree Mech said:

Also, could I be missing a third spring or linkage that I am not seeing in pictures or schematics? I am not understanding how it knows to back down the throttle from high to low. I haven’t been convinced that I’m not missing something.

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From what I can tell about governors, there's got to be a jeanie inside the block that makes this all work.

Bad Governor, back in service again.