Kohler KT730-3047 MTD engine on Cub LTZ 42. It si only 5 years old. Just replaced carb, fuel pump, filter (both fuel and air) plus new plugs. It had set up all winter with fuel. It runs but surges then speeds up, surges and shuts off. Any suggestions? It has been a while since I worked on my equipment.
Surging on a governed engine is just about always because the fuel being supplied is insufficient to maintain a constant speed.
So either you are not getting enough fuel for the amount of air entering the carb .
or there is an air leak after the fuel has mixed with the air.
If it was a cheap carb bought on line then there is a better than average chance it is faulty .
That means you have floating debris in your fuel tank, so you ain't out of the woods yet.
Drain the tank remove the cap and let it dry fully
Then blow back through the fuel outlet to hopefully blow the crud out of the tank.
