Engine running rich

[James6138]

I have a Briggs and Stratton 500 series engine that is running too rich (if I spray a small amount of starter fluid in the air intake it almost dies)

Pretty new to this so I'll try to list everything I've done, and hope to get some help with this thing while I still have hair left.

It's one of the plastic carbs that mounts onto the gas tank, I have got the rebuild kit and replaced the screen, gasket, diaphragm, and spring. I have checked the intake manifold and it is secure, not cracked and has no leaks that I could find (sprayed starter fluid around the gaskets to see if it changes how the engine runs)
I removed the flywheel shroud and verified that flywheel key looks intact and not shifted. I am getting spark as it does running, just very choppy.

If I manipulate the auto choke cable and run it almost completely choked out, I can get it to run fairly normal, but when I left go it just does its surge thing again and takes on too much fuel.

Hope someone can help or point me in the right direction

 

[logert gogert]

Does your carb have a adjustable mixture screw?

Also, please post you engine model numbers.

 

[bertsmobile1]

Opposite to what you think.
Surging is always caused by not enough fuel to support the speed the engine is runnng at
So either the carb is not supplying enough fuel ot air is being sucked into the engine after the carb.
Remove the blower housing again and check the long manifold tube that runs across the engine.
These are prone to cracking & splitting usually on the under side where they get full heat from the engine.
Be careful with the tiny 1/8" bolts that hold it in they are really easy stripped.

 

[Rivets]

The new 500 series engine have a problem with the jet assembly clogging, causing a lean running condition. There was a change in the design, but still the problem can exist if the engine is allowed to sit for extended periods of time with fuel in it. Will probably need to clean jet assembly or replace carb.