Briggs 14.5hp...Model 287707...Type:1272-E1...Code 9850623. Put on choke to start...Put on Max Speed after it starts. Runs and mows great!!! Pull throttle lever down to idle or shut down and nothing changes. Motor still running at max speed. The throttle cable is adjusted properly and the screw is tight for no slippage.

When engine is RUNNING at max the governor arm is fully forward and the throttle plate is closed. When engine is OFF and the throttle cable set at max speed the governor arm is fully back and the throttle plate is open. Slide the throttle cable down to stop and the governor arm goes fully forward and the throttle plate is closed. Blowing my mind!!!!

This is on a newly purchased 42" Murray Mower with an automatic transmission. All imput would be appreciated!!!!

Checked the screws on throttle plate and they are fine. Left that out in my original post

sounds like the governor isn't doing its job much, should be a spring right there i think.

This is on a newly purchased 42" Murray Mower with an automatic transmission. All imput would be appreciated!!!!


according to the code of that engine that thing is a 1998 wow seven years old ( alot of setting )

not sure what you are calling the throttle plate ,,, but there are two round butterflys one is choke one is throttle , sounds to me like someone might have robbed the throttle or it might be stuck @ wide open throttle (wot) can you get the engine to idle down by moving the linkage by hand .. does the governor arm pull back feel like it wants to pull on the linkage to the carburator towards the idle position when its @ full rpm ? but if its under warranty take it to the shop i have seen quite a few of the Model 287707 grenade the engine should not run over 3600 rpm s

not sure what you are calling the throttle plate ,,, but there are two round butterflys one is choke one is throttle , sounds to me like someone might have robbed the throttle or it might be stuck @ wide open throttle (wot) can you get the engine to idle down by moving the linkage by hand .. does the governor arm pull back feel like it wants to pull on the linkage to the carburator towards the idle position when its @ full rpm ? but if its under warranty take it to the shop i have seen quite a few of the Model 287707 grenade the engine should not run over 3600 rpm s This is a used mower I purchased a week ago. The throttle plate I'm referring to is what you call the throttle butterfly. The only rod on the carb is the rod with a long skinny spring running to the throttle butterfly hooked to the governor arm. There is a heavier spring down towards the bottom of the governor arm hooked to the throttle slide. When the engine is running at max speed the governor arm is fully forward with the throttle butterfly fully closed. How can it run and mow so good if the throttle butterfly is fully closed as if it was shut down? If you push the governor arm to the rear of the engine the throttle butterfly opens and the engine revs higher. Thanks for your imput!!!!

sounds like the a "heavier spring down towards the bottom of the governor arm " might be the problem , or you can try starting from first base , to adjust the governor arm ; with the engine not running move the throttle to wide open and watch the governor shaft coming out of the engine break the bolt loose hold the throttle wideopen and turn the shaft the same way as far as it will go hold it and tighten up the bolt that sets it , look @ the spring and make sure it is not twisted should be kinda loose where it hooks in to the throttle control plate and the governor arm , you might look at the plactic slider on the throttle control plate make sure its not broken but if the governor is not pulling the throttle back to idle position , if you cant get it to go to idle the governor must have slipped or the linkage arm might be too short or the spring might be hooked in the wrong spot or the linkage might be in the wrong side of the throttle shaft @ the carburator ,, did you try taking the throttle cable loose and sliding it in ? the throttle cable might be too short , also how did it start acting up was it like this when you bought it ? ?

I Give Up!!!! It runs and mows perfect. Just won't idle down or shut off unless you choke it or turn off the key. Everything looks and checks out OK!!! The choke (plate with two holes) is wide open when running at max speed. It's not over revving.

The big issue here is...........how can it run so good with the throttle plate completely closed????? It's got to be getting air from somewhere!!!

Thanks for your imput.

carbs on tight? gaskets good? is that spring there and working? on the governor?

Yep!!!!! Gaskets are all good and tight and the spring is there and working. I'm through fooling with it. It runs and mows perfect. Maybe the plastic carb housing has a crack and it is sucking air. If it ever quits doing it's thing, I'll get serious and pull everything down and recheck everything.

Thanks................

unless someone maybe worked on it and cracked that maybe, or lost one of the linkages and replaced it with the wrong one....