An electrical part is failing, Which part you ask IDK.
When you turn the key,does the starter turn the flywheel hard enough to start the motor? Or is it turn key nothing happens at all no sound,no starter nothing.
If nothing happens when you turn the key, leave the key on and get a large screw drive put on thick rubber gloves, and touch the two large terminals of the solenoid, if the motor tries to start or runs you know it's the ignition switch. If you don't feel comfortable doing this You can test the solenoid with a multi meter it's very easy,u-tube explains if perfectly.
I would remove all you battery cables and clean all connections shinny,coat with dielectric grease reinstall them with nylon locking nuts,never wing nuts
Low odds maybe the neutal interlock switch, it's called something similar for your motor.
Do you have diagnostic software for your motor.
If you get desperate, it's prime boating season, and you have the money to throw at this, this is assuming you cleaned all your battery connections first ,You replace the ignition switch, pull one wire off put it on the new switch, replace solenoid if if didn't test ok or you didn't test it,, replace neutral interlock/safety switch they will know what you mean.
