87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

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SFORCES

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I bought a 87 Sea-ray Seville 17.5 boat of a Guy that was restoring it and put in a MerCruiser 120 HP 4 cylinder motor in But got sick and can't finish it. now i got to figure out what wire' go to what. It has a 8pin round plug from the original motor to a 8 pin square plug under the Dash. How ever that plug won't fit into the 120 replacement engine. it's a 8 pin round connector too but the pin are different. on the original factory wire harness the colors are Yellow/Red, Blue, Tan, Brown/White, Grey, Black, Purple and Red/black. however i don't see a red/black wire. now on the Replacement engine the color code is Pink/White (might be red/white) White, Brown, Green, Yellow, Orange, Black, and Red. I've looked all over to find out the manual for this engine all he told me it was a Mercruiser 120 HP 4 cylinder. Can anyone point me in the right direction. i want to use the harness that came with the 120 hp and cut the end off on the original and run that harness to under the dash so i can splice in the 8 pin square plug for the dash etc.
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Hmm.. i look that over and i guess it's still over my head. Could some one enlighten me?
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

I looked for the serial # for the engine and it said 2220205 but i can't find anything on this serial #. the last digit look's like a 5 but not sure
 
Don S

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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

SFORCES said:
I looked for the serial # for the engine and it said 2220205 but i can't find anything on this serial #. the last digit look's like a 5 but not sure
Click to expand...

The reason I asked for the serial number was to determine the engine year. In this case, it's a 1969 model, and the wiring is completely different.
In 87 when your boat was made, Bayliner used their own wiring harnesses from the engine to the instrument panel, but it did plug into the electrical plug on the engine. The good news is they used Mercruisers color coding. However, the 69 engine has the Pre BIA wiring color codes and the boat is using the BIA coloring codes.

Does your engine even have the round 10 pin connector plug on it? The early 120 (have no idea of the SN range) used a terminal block instead of the round plug.

The other problem is the 120 engine used an ammeter on the dash and your 87 has a voltmeter. This makes the wiring physically different and needs to be changed on the engine to eliminate the ammeter.

If it was my boat, I would take all the wiring off the engine, and start over and rewire it to the 87 wiring diagram.
 
Don S

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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Ok, I put together a couple wiring diagram files for you. One is for your 69 engine, there are two different ones, not sure what you have. You will have to verify which one to use by looking at the engine.

View attachment 167667

The next one is for your present wiring on your instrument panel, and I included the one for the engine so you can see how it is wired with todays wiring color codes.

View attachment 167668
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Don S said:
Ok, I put together a couple wiring diagram files for you. One is for your 69 engine, there are two different ones, not sure what you have. You will have to verify which one to use by looking at the engine.

View attachment 167667

The next one is for your present wiring on your instrument panel, and I included the one for the engine so you can see how it is wired with todays wiring color codes.

View attachment 167668
Click to expand...

I tired to get the attachment but i get an error

Invalid Attachment specified. If you followed a valid link, please notify the administrator

i can take pics of the engine and plugs if you need them? also it doesn't have the throttle so i dan't know what one came with it. he had one but i think it might be to big for it
 
Don S

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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Not sure what happened to my links, but they don't work for me now either.
Try these.

View attachment 69 120 wiring.pdf http://forums.iboats.com/attachment.php?attachmentid=167764&stc=1&d=1347403331

View attachment 87 120 wiring.pdf http://forums.iboats.com/attachment.php?attachmentid=167765&stc=1&d=1347403349

For some stupid reason, the preview image doesn't work from manuals 1 and 2, so I put a link to the .pdf file next to the thumbnail.
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Here is a pic of the boat engine harness and the connector on the engine and the engine its self.

Boat Harness.jpgEngine Harness.jpgEngine Plug.jpgMerCruiser Engine.jpg
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Don S said:
If it was my boat, I would take all the wiring off the engine, and start over and rewire it to the 87 wiring diagram.
Click to expand...

How can i do that? Can i get a connector and swap out the one on the 69 engine so i can use the original harness with this motor? do you know what this boat originally came with? i'm not sure what they call it circuit board on the engine?
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

What would i need to do to rewire it to the 87 Wiring Diagram?
 
Don S

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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Take all the old wiring off the engine. Then buy new wire the correct size and color (when possible) and make a new wiring harness. You will have to use a terminal block instead of the round harness connector because they just don't match up.
You will also have to go to a Merc dealer and get a resistor wire to build your new harness with.

Problem I have, is I'm not sure you have a 69 motor there, or what it is. What alternator is on that engine now, does it have an external regulator? The ballast resistor is wrong for a true 69 engine should show a dual resistor.
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Don S said:
Take all the old wiring off the engine. Then buy new wire the correct size and color (when possible) and make a new wiring harness. You will have to use a terminal block instead of the round harness connector because they just don't match up.
You will also have to go to a Merc dealer and get a resistor wire to build your new harness with.

Problem I have, is I'm not sure you have a 69 motor there, or what it is. What alternator is on that engine now, does it have an external regulator? The ballast resistor is wrong for a true 69 engine should show a dual resistor.
Click to expand...

Can you point me to were i can get a terminal and what kind and what resistor to get. What Gage wire should i get? could i just use the wire that is the original 87 wire harness and just cut the end's off? or is it better just to get new?

on the engine on the bottom right side i got some # 3849449 or it would be 8849449 can't tell also there is OH186 con2 i think that it's an OH in front of the 186 can't really tell. on the alternator it's say's 1100721 32a 6L17-12V neo how can i tell if it has an external regulator?

also can you tell me how to take off the side panel so if i need to run new wire i can.
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Well i guess there is no more i can do unless i can figure out what engine is in this boat. don't want to get the wrong stuff to rewire it or what ever.
 
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Re: 87 Searay Seville 17.5 & Mercruiser 120 HP 4 cylinder Wire diagram

Don have you found anything else on this engine?
 
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