Engine surging while running. Dies after a few seconds unless I hold the choke on,

Possible air leak in the fuel system. Make sure everything is tight and no lines off. Holding the choke on enriches the air mix.

Thanks for the help. I think I need to replace the spring on the upper linkage. I do not know what this part is called, but it is a black piece of metal attached close to where the throttle cable meets the motor. The "spring" is wrapped around a long rod. The end is attached to the engine side of the carb. Looks like maybe an RPM limiter or something. I noticed earlier that the spring was not attached by the carb, so I attached it. Mower ran well for a few minutes than died. Upon inspection I noticed that the spring had come loose again. I hope that is all it is. I also ran some Seafoam in the gas to clean everything up. Hope it works!

Hi,
The spring you refer to holds the linkage to eliminate slack that would cause the engine to "hunt."
Sound more like dirty jets.
Peace,
Clarke