OK. It's been a while but the boat is back home from storage.
No start. Fuse at starter good. Shifting the shift arm around no help. Switched the shift safety relay from port to starboard, no help. How do I "hotwire" starter to jump motor. What wire goes where? It's hard to see down there.
Could be the starter solenoid itself? No clicking or nothing. Gauges have power.
HEEEEELP. !

Have you done this and if so what was your findings?

Yellow wire with the red tracer on the starter solenoid, jump across that one when the ignition is turned on.

Not even sure where that relay is. There is a relay looking thing on the left side near the computer with red and yellow wire. Looks ok. I will try to get a read on it, but I have to find my meter or buy another.
THX
P

Starter solenoid is bolted right on the starter itself.

I know, I was referring to the other comment testing voltage.
On a note, normally when there is current to the starter or solenoid, the gauges make a move, they drop since there is a current draw.
When I try to start, the gouges do not move. I'm thinking there is no power to the starter/solenoid to activate.

The slave relay has 2-yellow/Red wires on it, one larger the the other. The key energizes the slave which in turn sends power to the starter solenoid. If your not getting power on the small yel/red wire when key is turned, the relay doesn't close. If it does get 12V and still doesn't close then its a bad relay or the small ground wire on the relay may have broke ground

You have small square relays, not like what's shown in pick but does the same thing

OK. I rigged a wire to the yellow wire on the solenoids. (I hoe it was the yellow, hard to see, just feel, but the yellow ended up on a small bolt.
Touch the large red cable on the unit. Sparks, my jump wire get pretty hot. So... There is current to the starter. Starter would nit engage,due to holding the wire for a second, since the sparks.
Ok what next? New Starter?

How could I check the starter "slave solenoid?

If you where jumping at the starter and not the slave relay, then the starter may be the issue
Did you jump from the starter post to the yellow/red wire on the inside of the starter?