If you've not already removed the unit, I would spend $40 bucks (probably on $20 in the states) and install a Supco SPP hard start kit (piggy backs onto the current capacitor - I believe the Cruisair is a Dometic product). It may work and/or lengthen the life of your current unit,
https://www.amazon.ca/gp/product/B00...?ie=UTF8&psc=1
Check the Amazon comments
I would think you could buy a complete new Dometic A/C unit that was much more efficient and more BTU's even for <$2,000 (
https://citimarinestore.com/en/self-...207500316.html), but I would try the $40 fix first, imo