wiring diagram

[redbay11]

hello
i have Yamaha ME 421 sti engines. can any one help me. i need a wiring diagram for the engine. when i turn the key no lights or alarm comes on. it did come on once but when i tried later it didnt work, for some reason the one way diode is disconnected but even with it connected it does not work.
i hate electrics

cheers

cam

[Jelly]

Cam
That sounds like you have main power issue, have you checked the fuses, kill cord switch and the earth cable from the rear of the engine to the battery.
The Yamaha manual is worth getting.
Good luck
Jelly

[outboardtech]

your best bet would contact BBMS Marine Swanick and speak to Paul . He is the MAN you need to speak to on this . He will help you out .

[mickyspec]

have you checked the fuses that are found beneath the black engine mounted cover ?
also check the wiring harness where it plugs into the control unit "black box thingy"

[biffer]

down the side of them engine where the control cables are there is a round tube inside it is a 100 amp fuses check, you've probaly blown it, it may be cable tied to the bracket below the turbo

[yam diesel man]

[QUOTE=redbay11;284143] hello
i have Yamaha ME 421 sti engines. can any one help me. i need a wiring diagram for the engine. when i turn the key no lights or alarm comes on. it did come on once but when i tried later it didnt work, for some reason the one way diode is disconnected but even with it connected it does not work.
i hate electrics

cheers

cam [/QUOTE
wondering if you found out the promblem with your instruments not lighting 100 amp fuse gone or check the 2 eye turminals all starter motor stud they can get abit gruby so clean the off with a bit enry tape . i work on the hydradrives everday i know them off the back of my hand any problems in the future gives us an email glad to help

[cdilljr]

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.

Charlie

[Erin]

Your symptoms sound so much like a dodgy starter, that if replacing the starter didn't cure them then I'd be looking closely at the main power wire from battery to starter and checking carefully for corrosion. Don't forget the negative return wire too. I would think your corrosion problems with the starter and alternator will have affected other bits too. Perhaps try some jump leads and a fresh battery.

[ashbypower]

3 Years plus, close to the record !!