What could cause a surging problem on a Honda gx120?

Answer by  HumbledbyFaith (24)

The governor rod connected to the carburetor. could cause a surging problem. The a faulty carburetor. could cause surging also. To isolate the surging prodlem, hold the governor rod while the engine is still running. If the engine stops surging then your problem will be in the carburetor. linkage. If not, your problem will be in the carburetor.

Answer by  Mark89 (173)

Surging as described is likely due to a clogged fuel filter. I would suggest replacing the fuel filter and if that doesn't solve the problem I would drop the bowl on the carburetor and clean the main jet. If that still did not solve the problem I would check the governor for a broken spring.