Wiring Diagram? ME421 STI
I'm in Yamaha Diesel Sterndrive Hell - otherwise known as the USA. Long, sordid story that I think involves lawsuits, Departments of Commerce / Justice, etc. End result - ZERO support for drive or engine in the US. Most mechanics not only shy away, but rather run away. So I'm in a pickle and need to lean on my European friends for help and advice so I can help ease the tension with my mechanic.
At the moment, I'm having electrical malfunctions. Seemed ok, but alternator was seized completely due to corrosion after water sprayed around engine compartment (different story). I managed to cross reference Yamaha / Denso to a Prestolite match here that matched perfectly except for the pulley which I swapped out. After installation, new problems cropped up and it appears they were due to a circuitry difference that wasn't picked up in my cross referencing. I got 12v to the panel when the kill switch was in, but no activity to the starter. With the kill switch removed, I got no voltage to the panel, but the starter would work. Hmm. My mechanic did something (unknown to me), but told me all was well.
I bring the boat home, clean her up and prep for launch, turn the key to on, and get 12volts with the associated beeping noises. Turn to START and there's a click (solenoid type) from somewhere in the engine compartment followed by a rapid voltage drop and no actual starter activity. Repeat a lot, check batteries, keep trying. Suddenly she turns over and starts briefly. I immediately shut her down because my cooling water wasn't on. Turn on water, back to square one. A few taps on the side of the starter and voila - starts up, runs beautifully, excitement all around except I've now decided that the starter which only looks a little better than the old alternator did needs replacement. Again, Yamaha / Denso and then a cross to Yanmar and I have a brand new, shiny starter. Very excited. Hook her up, turn the key and sadness - same story, click, voltage drop. Put battery chargers on batteries to assure voltage - no change.
Then it got worse - after a few attempts, I now don't even get voltage to the panel, no beeping. Seems as if master fuse of some sort blew. But what fuse and where? I have no idea and am now trying not to lose my mind.
I know that a wiring diagram has great potential for help so if anyone has one available, that would be great. Of course words of wisdom would be an additional bonus. I'm confident that this is a straight forward wiring / short circuit problem, but I can't spend the rest of my life trying to guess.
Thanks in advance and I hope that someone patient enough to read my tome can help out.