Have Boat Questions? Ask a Boat Repair Expert.
Can you take a picture of the wiring, particularly going to the rectifier, and the switchbox? If you can't then can you do a detailed diagram of the wiring?
I'll be in and out and will respond as soon as I can.
What happens if you disconnect the gray tachometer wire?
Is the picture of before the CDI rectifier?
That's not the correct rectifier for that engine.
Your stator has both the alternator coils, the yellow wires, and the charge coils for the switchbox, which supply the power for the ignition. They are two separate circuits with no common connections. However if the rectifier is not working properly and backfeeding voltage from the rectifier to the stator it can interfere with the charge coils, the red and blue wires from the stator.
Since in your case the ignition doesn't work with the rectifier connected that would be the problem.
You can damage a rectifier by having the external wiring harness disconnected.
Put an ohm meter between one yellow wire from the rectifier and the red wire, everything disconnected. Next reverse the meter leads, repeat on the other yellow wire, what are your results?
From yellow to red is 30 ohms correct, now reverse the leads. So if the red was on the yellow wire, put the red on the red wire. What is the reading?
OK Yellow to red 30 ohms and when you reverse the leads so red to yellow 0 ohms correct? This on both yellows? Then the diodes are OK. All the other reading don't mean anything.
Can you do a resistance reading from the red and then blue wires to ground disconnected from the switchbox?
Is the switchbox properly grounded?
Your readings are OK for the stator charge coils as well.
Make sure the switchbox is grounded well.
I'll be honest from what you are posting I'm not sure what exactly the problem is. I suspect somehow the rectifier is still bad. The correct rectifier is simply a rectifier, not a regulator and has only three terminals two for the stator and one for the 12V+.
So I would try another rectifier. Other than that without working on it myself, I don't know. I have been working on those engines since new and never ran into this particular problem.
I hate to have you parts change but that may be the only way.
Just make sure the case of the switchbox, rectifier and the stator are all grounded.
Let me know if I can help further.