I was running the 790 and 5' Bush Hog today and toward the end, I was noticing more exhaust smoke than normal and possibly (not sure about this) slightly less power. It's got 500 odd hours on it of which I've put about 300 and the PO did 200 or so. It didn't run hot and oil was fine but I'm thinking I may have an injector going bad. That mower does put a load on the 790 when the grass is tall or thick but this seemed to be more than normal.
I've got to check the book and see if there is other service to be done. I've changed the hydraulic filter and fluid once because I wasn't sure what the PO had done. Oil change was relatively recent as well.
So far in order of likelihood I have:
- It was my imagination as it was hot and the mayflies were biting anyway.
- I might have some contamination in the fuel and should drain a quart or so and possibly change a filter.
- Injector might be going bad or at least need cleaning.
- Rings on one cylinder may be leaking a bit of engine oil. (I hope it's not this one.)
- Some other thing I haven't considered like the valves may need setting.