It did do that. I was told that is normal on these motors until their warm or not under load. Something about the way the carb setup. Never ran a push mower with bbc so I wasn't sure what's normal.
My riders don't do it but being hydraulic I figured well they are under load if even just slightly to turn the hydro pumps.
In hind site I feel like I should have told him no dice, or requested a different one. But I do or, should i say did trust him for the most part.