testing as follows. all viewed from rear of boat
forward stick =right prop clockwise left prop anticlockwise.
in tank mode= left stick works left motor. right stick works right motor AND rudders, Is this ok?
in mode 4 = rudder stick alone has no affect on motors. throttle then either rudder makes the outer motor stop each time.
in mode 3= right rudder only and both motors turn anticlock. left rudder only and both motors turn clock.
right rudder then forward and right changes to clock.
left rudder then forward =right stops and reverses.
forward then right rudder=left stops and reverses.
I'm completely dizzy now, going for a lie down
Dave, at this stage, and even now, i dont know what if anything is at fault. as Colin says, it may well be my cheap transmitter. this kind of forum is made for this kind of question, many folk can help me resolve )ar at least diagnose) the problem even if it comes down to user error.