Newer model Isolated ground kit for Yanmar from alel
eric freedman <kimberlite@...>
I believe this is what you have. This is the newer conversion. I see the relay you are referring to. The only thing I do not see in photos are the dual wire senders. I do see that they used them as you can see a bunch of sender wires at the Valeo Solenoid. If you will notice they show that they are still using the diodes. They are covered in heat shrink tubing with a solderless connector at either end.
I also think I see a tranny oil cooler mounted on the tranny. Do you have this?
Above is the link and the wiring diagram of the newer conversion of the yanmar of the isolated ground.