Water can leak into the shift actuator, which may lead to internal corrosion and wire damage. Wire damage could eventually cause the engine to go into Guardian-forced Idle, loss of shift control (engine remains in its last gear position) or the engine may not restart. If engine power or control is lost, it is possible that the boat could become stranded.
What to do...
Stop using the engine and contact your authorised Mercury Marine dealer mentioning Mercury Outboard Service Bulletin 2019-01 Contact Mercury Marine Customer Service for more information.