Hustler Super Z won't start under 60 degrees

For the last few years my Super Z will not start unless the outdoor temperture is over 60 F. Under 60 degees it cranks slowley misfires until it drains the battery. If it is warm out it starts before you can let go of the key.

Help?

2018 Hustler Super Z HD37

Model: 937003

Briggs & Stratton

37 HP EFI Vanguard OHV Engine