Brigs 12.5hp engine revs full speed when I turn it on

[Eg2494]

Hello,

I have a craftsman riding mower 12.5hp model 917256451. I cleaned the carb and after putting it back on every time I start the engine it automatically starts running at full speed. I put it on choke and it starts and runs fine but then when I move the lever to run the engines goes full throttle.

I’ve checked the carb installation against the manual and everything seems fine. I also adjusted the throttle cable per manual instructions.
One thing I noticed is that the throttle butterfly on the carb is loose and there is no spring to it? Might this be causing the issue?
I don’t recall there being a spring.

any ideas on what else to check before I start messing around with the governor?
Thanks in advance!!

 

[Rivets]

Using this service manual double check how you installed the linkages. I’m thinking you may have hooked it up wrong. https://www.manualslib.com/manual/8...tton-Twin-Cylinder-L-Head.html?page=70#manual

 

[StarTech]

Using this service manual double check how you installed the linkages. I’m thinking you may have hooked it up wrong. https://www.manualslib.com/manual/8...tton-Twin-Cylinder-L-Head.html?page=70#manual

But Rivets it is a single cylinder L head so that SM is of no use.

289707-0179-01 if original engine.

Here is the basic linkage for this engine.

 

[bertsmobile1]

Most carbs are universal so the throttle has holes for pushing on or pulling on
Very easy to get it backwards
Same story for the choke but at least most chokes have a open spring

 

[Rivets]

Sorry, grabbed the wrong manual. Here’s one for single cylinder. https://issuu.com/heydownloads/docs/001-027_briggs_stratton_single_cylinder_l-head_eng