23hp briggs won't run when it's hot.

I Googled this in 15 seconds. Here's the manual in PDF:
http://www.husqvarna.com/ddoc/husi/husi2007_usen/husi2007_usen__539131361.pdf

Husqvarna Z246 Briggs and Stratton Zero Turn Mower ...

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https://www.youtube.com/watch?v=Ohx8nxNrgNs
Feb 23, 2015 - Uploaded by SleEquipment
Husqvarna Z246 Zero Turn Lawn Mower 46" - 23 hp Briggs and Stratton Engine: Briggs and Stratton ...

Hi Sue,here's a link to your Kohler engine list of user points. http://www.kohlerengines.com/maintenance/faqs.htm

David the fuel filter in the tank has become clogged. It needs cleaning.

Model, Type and Code are required if this is a Briggs and Stratton engine. Thanks; George

Yes you need to drain the oil, turn the engine onto its flywheel, remove all the crankcase screws, clean the exposed crank to remove any rust or dirt, now gentlty ease the base off, it should come away with the oil pump gear.

magnito problem sound like

After a very extensive cross reference session your engine is model number
10H902-0285-E1 (not provided by you so it took a while)

Your engine is covered in this repair manual:
http://www.mymowerparts.com/pdf/Briggs_&_Stratton_Service_and_Repair_Manuals_Spec_Charts/270962%20Single%20Cylinder%20L-Head%20BRIGGS%20&%20STRATTON.pdf

If there is a problem that your having I can help you if you would just elaborate. I could save you lots of time. The 2 most common failures of this engine is on the carburetor. The parts that fail are the diaphragm (Item 394) and the primer bulb (Item 976) of this link:
http://www.partstree.com/parts/?lc=briggs_and_stratton&mn=10H902-0285-E1&dn=57160004

Carb data is in section 3 of the first link.
Thanks for choosing FixYa,
Kelly.

I think you have the rocker arm clearance set wrong on the one that you worked on.
See if this video will help -

Lawn Mower Repair Valve Adjustment Twin