Plus as Rivets some of us work all week at our own shops. Personally my shop is operated 6 days 10 hrs/day every week. Sundays are my day to get my own things done. I only stopping now as I awaiting a couple of my gals to lay. Then I going the grocery store, Auto parts store, HFT a couple items and then when get that done it my housework and yard work plus formatting and updating my business software with new price files.
Now we also need the actual model numbers of mower and the model and spec numbers of the engine for us to see what you in front of you as we are not all seeing.
Now there three base versions of the Kawasaki 691V (FS, FR, and FX). Idle speed is set at a base of 1450 with a governed idle speed of 1550. If not done correctly then governor will act up.
From the service manual these are the idle speeds
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Also note that just because the hydro oil was change does not mean something else hasn't happen in the meantime. I just had a mower that was running when the customer picked it but before it got unloaded at the customer's home it started acting up. A piece of metal that another didn't keep track of started causing problems.