Hey I have a kobelco ed 150 that was caught in thesearch California floods. Took water up to the base of the engine.The equipment was retrieved changed batteries and starter. It ran great after for a couple days. Went to start it up today and it has a step motor Ng code and a e/G Rev code. It starts but sounds like it's only running on 2 cylinders and won't idle up
With that much water in it most likely has water in the wiring harness maybe even in the computer.
Measure temperature at exhaust ports to check if all cylinders are firing. Try to manually rev up engine.
Do NOT grab the stepping motor with the key turned on or the engine running it will cause major and expensive problems! If you want to see if it will rev up unhook the stepping motor first.