On DuraForce Lawn Boys, there can be several issues when it comes to surging. Number one, they often did that off the showroom floor due to EPA restrictions and your altitude. It could also be a lean condition due to a plugged jet or both jets. It's leaking air from a failed seal. The screen could be clogged. It can also be caused by a nick in the plastic throttle linkage creating too much resistance or sticking. It could be the spring stretching/failed on the throttle link to the governor. It could be slight heat warp on the carb body binding up the throttle link. The outside of the carburetor and connecting linkages could simply be dirty. Or any combination of the above.
You state the pilot jet as the sole/main cause when it isn't always that on Lawn Boys. And what I listed here isn't the same as the F or D engines. You always start simple and work to toward the complex solution.
You state the pilot jet as the sole/main cause when it isn't always that on Lawn Boys. And what I listed here isn't the same as the F or D engines. You always start simple and work to toward the complex solution.
