it's cool that you got into three wheelers that's not a honda. once you get into the nuts and bolts of these things, you'll realize just how simple these trikes are. since you have 2 similar trikes, if you think it's a coil, swap them between the two. just dont leave parts off the first trike. like others said, it sounds like a fuel issue, petcock, fuel line, filter.
I wished we could get decent money local fkr trikes, I'm lucky to get 3 to 350 for a running 185 or 200s. jim
81 185s
82 185s with 85 200s motor
82 185s
and a 72 ct70