Briggs running very fast

[MarshMarlowe]

Engine: Briggs & Stratton Intek 19.5HP
Model: 31p677-4373-G1
Mower: Poulan Pro 300EX / model PB195H42LT

I just recently picked up a neglected Poulan riding mower. This is my first riding mower, and I have little to no experience working on small engines. I recently disassembled and cleaned the carburetor after watching several YouTube videos and reading some how to's. The carb was very clean and the process to disassemble and reassemble seemed simple and straightforward, but I suppose I could have missed something.

I started the engine for the first time today, and it runs alarmingly fast. I tried reducing the throttle via the throttle lever on the dash, but this had no effect whatsoever. The throttle plate is wide open in the carb, but it seems like the governor isn't doing its thing. When I move the throttle lever down, a plastic slide moves on the side of the engine, but it doesn't seem to be connected to anything. Anyway, I shut it down pretty quickly.

In case I boogered up the the throttle linkage on the carb, here are some pictures of how it's currently set up:




Now when I ran the engine today, I was only testing it to see if it would run so I did not have the air filter attached to the carburetor (I removed the plastic bag you see in the picture as well). Could this have anything to do with it running at such high speed? Could there be an air leak where the plastic tube connects to the engine? Am I missing a piece of linkage, or do I not have the linkage routed correctly? Leaking head gasket? It wasn't smoking ...

Thanks for any help

 

[cpurvis]

Take a look at page 8 and find spring #209. Is it in place on your engine?

http://bsintek.basco.com/BriggsDocumentDisplay/18ktxKXUnfBhU7y.pdf

 

[MarshMarlowe]

Take a look at page 8 and find spring #209. Is it in place on your engine?

http://bsintek.basco.com/BriggsDocumentDisplay/18ktxKXUnfBhU7y.pdf

If this is the spring, then yes:

 

[MarshMarlowe]

I've been doing some reading about adjusting the governor. I will give that a try and report back

 

[cpurvis]

Does that spring stretch and contract when you move the throttle back and forth?

 

[MarshMarlowe]

Does that spring stretch and contract when you move the throttle back and forth?

Yes

 

[cpurvis]

Ugh. I was hoping that wasn't the case. I think that means that you'll have to dig into the governor. Check the bolt at the bottom of the governor arm that clamps it to the rod connected to the throttle shaft on the carburetor. Make sure its tight and the shaft it attaches to rotates with the governor arm.

 

[MarshMarlowe]

Well the governor arm was tight. I tried adjusting the idle speed screw on the carb, and that seems to have fixed it Thanks for the help

 

[bertsmobile1]

Just remember that the governor slows down the engine.
It works against the throttle via the spring

 

[MarshMarlowe]

Thanks for the clarity