No Start/Then Start - One For the Experts

[ToddW850]

Okay, I'm completely STUMPED on this one. Curious what the experts think.

Background
2017 Yamaha 242X
Boat has performed without issues since I bought in 2019.
Took out twice this year, no issues. After last outing in May, starboard motor wouldn't start. After raising the engine hatch, I could hear an on/off click with about 5 seconds in between. If I pushed the start button 4-5 times, it would start. Once it even started in between the solenoid clicks. Check again a week later and only clicks, won't start no matter how many times I try. Ruled out fuses, switches, etc... Used a pair of insulated pliers and jumped the solenoid. Motor started!

Ordered OEM solenoid and installed it when it arrived the other day. Hit the start button and NOTHING. Not even the ON/OFF click like before I swapped it. Installed the old solenoid back on and no click anymore either.

Put the new solenoid back on again and swapped the starter buttons. Button is good because it started the Port motor, but the Starboard motor still won't start.

Last ditch thought tonight. Decided to swap the new solenoid on the Starboard motor to the Port motor. And the old Port solenoid to the Starboard motor. Now BOTH motors start without issues! WTF??

I started both several times and all seems good. But what in the world caused this? Does anyone have a guess? I'd love to know, because it makes zero sense to me.

Thanks

 

[CastawayRK]

Bad/corroded ground that got scraped clean enough to work with the swapping around? I don’t know how hard it is but in the name of science swap em back?

 

[ToddW850]

Not hard to swap. Hardest part is leaning my body over to reach them haha. But good idea. I'll wait until Winter and mess with it again.