I own a Hustler Raptor Flip Up 54" mower with the Kohler 25hp 7000 Series engine that I purchased back in Aug. 2016.
Definitely not an expert here but just going to give you my opinion, experience, etc.
First off, my manual says "allow the engine to idle two minutes before advancing the throttle and /or engaging the deck clutch" prior to actually starting to proceed to cutting, etc. found out that if this is not performed the it becomes a factor when actually beginning to first use the mower. If not properly warmed up the mower will stop/cut out when mowing.
So read your manual section on "starting your engine" for your specific Hustler style/model/type of mower and see specifically what it says?
Also it is important to "never" use old gas and use gas with an Octane of 87 or higher.
Also when finishing cutting grass let the engine run idle for 2-3min. with the throttle on mid to low before switching off.
The best advice I can give you about all this is to go back and read your manual real good so that you get more or less an idea on how to handle that Hustler mower.
Good Luck and hope everything works out well for you.