oscillating 15 HP kawi

[EMJ]

I have a Scag WB with a 15HP Kawi fh451v. It started to oscillate at an idle. Now it is oscillating at full throttle when it is not under a load. When the mower deck is engaged it runs good. What could be the problem? It is well maintained and is only 2 years old, not many hours. I am thinking maybe fuel pump? Any help would be appreciated thanks

[Restrorob]

Sounds like trash/water in the carb....

Take the carb. off then tear it down, Spray carb. & choke cleaner with the straw through ALL ports, passages and jets then re-assemble.