I was looking for a new coil, and they are almost half the price of a new tiller, and someone said the new ones had honda motors and someone posted a site for the mantis maybe refurbished ones I dont know
https://www.amazon.ca/CHIKURA-Backpack-Stroke-Cutter-Trimmer/dp/B07QMSWT23 Not necessarily this one but a back pack trimmer as opposed to just a regular trimmer. My old Stihl FS85 is starting to feel it's age like myself, both of us have maybe pushed it a little bit further than we should have...
Mantis uses both 2 (Echo) and 4 stroke (Honda) engines. You can get a new coil from Mantis or do like I did and get a used coil from an Ebay seller.
It cost me $32 4 yr ago but seem to be fairly common listing. If you do decide to replace the coil, make sure it's for the particular engine (mod #) that is on the tiller or it won't fit correctly.
Bought the Echo tiller about 3 seasons ago. Pretty much identical to the Mantis for less $$. It replaced a Craftsman tiller that I abused and overworked for over 20 years before it gave up the ghost. Have a 27” Echo chainsaw that impresses the heck out of me also. Both have made me an Echo fan.