This is a Briggs Model 287707 Type 1272-E.

I bought this engine used. It runs great but seems to over rive . The governor never kicks in under load at low or high idle. It idles too fast, and the low idle carb speed adjustment has no effect no matter which way you turn the screw.

All the linkage going to the carb is connected. (I have a 12 hp to compare with.) I'm guessing someone has by- passed the governor. But I'm only guessing. Governor's are new ground to me. I'm as lost as an Easter egg.

It's a great old engine. And I'd like to keep it that way. I have pictures of my linkage but don't think I can post them here? Thanks in advance.

Edited to say. I got some ideas from some youtubes. However i think this guy worked on mine.
The link.
https://www.youtube.com/watch?v=UIlpoVnWakQ

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i would start by adjusting the governor and making sure the throttle moves the full range. Also, look at the throttle butterfly in the carb to be sure it is closing inside. If so, and the governor is adjusted properly, then the internal mechanism of the governor is bad.

 

THanks cheese. The video link I posted. Is that the correct way to adjust the governor?? If so. My engine is mounted on a Snapper rear engine rider. May be a little hard to get to.But I'll give it shot.

THanks

 

Cheese, I tried to adjust the governor. Like in the video. Mine has a 3/16 nut instead of a screw. Anyway, It was already turned as far clockwise as possible. I checked to make sure the butterfly was closing. And it is. I also backed the low idle screw all the way off. Still no change. You could pull on the governor arm. And it would idle down just for a few seconds then work its way to screaming.

Beat down by it. I removed the air cleaner assembly and throttle linkage.. Now the weird part. I barely opened the butterfly by hand. Cranked it. And it was screaming with the butterfly just barely opened. I thought. I'll fix this. Thinking that backing off the fuel mixture screw would flood it out. I backed the fuel mixture screw all the way out and was holding it in my hand. The engine was still screaming. I screwed the fuel mixture screw back in. No difference.


Now you're most likely thinking he confused the fuel mixture screw with the low idle screw. I can assure i did not. Actually both were removed. The butterfly was stopping against the low idle adjustment plate anyway. The low idle screw was backed all the way off. And again.I was holding the fuel mixture screw in my hand.

So, my question now. How can an engine run like a scalded dog. Without a fuel mixture needle even installed ? I know you guys must think I'm crazy. This thing must be possessed. I could take it to my authorized Briggs dealer.But he's the one that sold and installed the engine one week ago today. However in his defense. It has gotten worse every day. I hope to never set foot there again. Besides, I'm not working. So I would like to save the bucks and maybe learn something in the process. ?

EDITED to say. Bottom line. The only way I've found to decrease the RPM's is to engage the choke. The more you choke it. The less RPM's. Which is of course a no brainier. I just hope someone will explain to me why the fuel mixture adjustment has so little effect on this engine. Usually carbs are super sensitive to fuel adjustments. The above mentioned test where done without the air filter housing installed.

 

At full throttle like that, the fuel mixture screw is doing pretty much nothing. The engine is getting it's fuel drawn through the main jet and nozzle. The mixture screw mainly affects the low speed and idle unless this has the high speed adjustment on the underside of the bowl. From your description, I'd say the internal governor has gone bad.

 

THanks for explaining, makes sense now. No high speed adjustment on this model. The governor is working a little at controlling the rives. Running a rich fuel mixture helps tame the rives. But makes for a rough low idle.

Repairing the internal governor would be over my head and likely cost more than the engine's worth.If I had a shop do it. Got any thoughts for limiting the rives without going inside for governor repair? Did i go about setting the governor adjustment correctly? I turned it clock wise like the video showed. If so. Any chance that bending the governor arm in either direction would help?? I had thought of making a shorter throttle linkage. But then the choke would not engage from the drivers seat. Any and all ideas welcome.

THanks.

 

The governor is working against the throttle? Can you rev the carb and feel the governor try to push back against the throttle to slow it down? If so, the internal governor might be okay. To adjust the governor, put the carb at full throttle and hold it there. Loosen the clamp bolt on the governor arm and rotate the governor shaft that sticks out of the engine in the same direction that it would go to rev the engine up all the way. Holding these both in that position, tighten the clamp bolt. That sets the governor. I didn't watch the video, it was a little lengthy and buffering a lot.

 

cheese, Just wanted to thank you for your advice and efforts to help.