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Engine wonbt shut off

korn

Member
Just installed a rebuilt alter

Just installed a rebuilt alternator in my 88 470 mercruiser today and all seemed well until I went to turn off the engine and nothing happened...it kept running until I disconnected the battery! The boat was already converted from the old charging systen to a delco marine 3 wire alternator! The old wires were coroded as was the whole inside of the old alternator! I hooked up everything the way it was before so I have no way of knowing if it was correct or not! Where exactly do the 3 wires go that are comming out of the back of the alternator? Any help would be appreciated!!!
 
Sounds like the sense and ign

Sounds like the sense and ign are reversed or the alt diodes went bad.reverse the 2 smaller wires.
 
"Presuming that the old altern

"Presuming that the old alternator was a one wire then you need to make some changes to convert to 3 wire as it has an extra 2 wires. One is volt sense and normally just connected to the B+ unless you want remote sensing on the other side of a split charge diode etc. The other wire is the filed energiser and should go thru a battery warning lamp which should light when ign turned on, then go out when alternator is charging. Let me know if you need any further info as I am a Marine electrician.

Anthony"
 
"OK, I switched the two smalle

"OK, I switched the two smaller wires comming out of the alternator...the engins shuts off...but...the volt gauge on the dash reads 16+ volts whan the engine is iver 1500 rpm! Is this bad or is it just a bad volt gauge? I noticed that one wire comming out of the alternator goes to the positive side of the coil...is this correct?"
 
"it would be very useful to fo

"it would be very useful to fogure out what alt you actually have and what the wiring ism, otherwise we are just stabbing in the dark and could cause further damage. Can you check with your supplier what they actually sold you? If I had to take a guess it would be a 10si, if you google Delco 10Si you will find lots of images with which to compare. Then we can determine exactly what connections it has, where it should go, and then what problems if any you still hve. Voltmeter guiages are not typically very accurate, but 16v sounds like more of a fault than a small over reading. It could be that the volt sense connection isnt wiored properley so its giving full output, or as suggested the regulator has been damaged.

Anthony"
 
The heavy red battery wire hoo

The heavy red battery wire hooked to the threaded stud with the nut goes to a red wire with a purple stripe that goes into a big jumble of wires near the starter. There is a rubber connector on the side of the alternator with a black and a red wire comming out of it! The red wire is routed around to the other side of the engine and is spliced into an orange wire that liiks like it goes to the starter! The black wire from the connector is connected to the + side of the ignition coil! I hope this helps you guys out!!! Your help is greatly appreciated!
 
"Ed you have a Mando alt. the

"Ed you have a Mando alt. the black wire is really purple,exciter wire(+ side of coil). use a good meter to see what the alt. is actually putting out."
 
"to vbe honest its very hard t

"to vbe honest its very hard to help any further without knowing exactly where these wires go, just saying they go into a jumble doesnt really help me undersdtand what it connects to. I think you really need to follow each wire exactly and draw a little sketch showing what it goes to and the colour of each wire, also noting if the wiore changes colour (sorry 'color' for those of the in the US!).

Anthony"
 
If its the exciter then it sho

If its the exciter then it should prob have a resistance wire in between the coil + and the alt.
 
Regarding my earlier post i di

Regarding my earlier post i didnt see the "470" .You`d be much better off using the GM single wire instead of cutting into the harness and adapting a 3 wire.
 
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