6hp B&S with LMS Flo-Jet surges

[LA1]

I have a junker I picked up from the curb. it has a non adjustable LMS Flow-Jet carb. I tried a second carb of the same type still surges and sputters. I happen to have an old LMS that has the idle adjustment put that on and adjusted the mower runs nice now. The first LMS I tried I took apart cleaned , did not remove the welsh plugs, just cleaned with carb cleaner, replaced the valve seat. is the engine worn past a point that the fixed adjustment card can deliver or deliver too much, the plug looks ok so I am thinking running too lean, maybe not?

 

[mechanic mark]

Welcome to the forum. Post model xxxxxx, type xxxx, and trim xx from engine.

 

[smallenginemechanic]

I'm assuming you have been flushing the fuel tank? If there is any fuel filters make sure you service them. Check the plug and see if its white or dry and that will tell you its starving fuel.