I have two jj1800 full auto start
One destroyed it self on take off (saved the boomerang XL) the unit seized the rear bearing and I don’t believe it is worth repairing and neither does JJ
sent it to jj for warrenty was sent back unrepaired with quote of $900 (approx) only the outer case and starter are left.
Mounted the second in the boomer and rear bearing on this one began to rattle after two flights.
Have tossed them under the bench for a later project. Maybe