I have a Kawasaki FD791-CS04 on a 2006 Scag Turf Tiger with around 700 hours.
The engine is a 29 horsepower, liquid cooled, with DFI - so no carburetor.
The engine has fresh OEM NGK plugs, new gas, oil, new oil filter, air filter, etc.
The engine starts up and runs beautifully cold. Very smooth, quiet, and even. The engine also works very well under throttle hot or cold.
My issue is specifically once the engine is warm when the mower is in neutral. Once warm, as soon as I move the control levels to center, or open them to neutral, the engine beginssurging. It does this at both high idle and low, but is much more noticeable at high idle.
I have not had it completely die on my yet, but it does seem like it might if left there long enough.
Any suggestions on where to start with diagnosing? If it had a carb, I would start with cleaning, but the engine is fuel injected. From my googling I have seen a few suggestions on potential sources including the governor, the ECU, and something in the fuel delivery system but am not completely sure how to test those components. The service manual calls for an expensive specialty tool to test the ECU which costs almost as much as a new ECU. I do have a digital tachometer coming but not sure how best to use it to diagnose.
Secondly, how big of an issue even is this? If I don’t spend time and money tracking this down is it likely to cause larger issues over time?
Thanks in advance!