Hi I always seem to have problems with them i had a good one till the servo came loose engine went full power coupling destroyed itself

changed my prop shaft to 5mm so i could use a steel one i had

1st run went fantastic till i got a bit too close to the bank gave it a sharp turn boat jumped out the water it over throttled the coupling came loose again put it back together last night filled it with slow setting epoxy hopefully the grub screw not come loose going to try it again today it go,s again going to try a spot weld that hold it lol

has anyone else had problems with coupling if so how did you cure it

im running a jet stream 800 i changed it from ep to nitro using a force 21 engine