Needing Wiring Assistance After Engine Swap

[Bimmerknut]

Not going to bore you with an essay on the history of this boat. I'll gladly answer any questions you have however. So for the sake of being brief with the immediate issues, I'll share just the pertinent stuff.

- 1976 Fiberform 24ft w/Ford 151 - despite sitting 2+ years I got the motor running trim and electricals all worked (good news) - (bad news - cracked block)
- Swapped the motor out with a known good Chevy 350
- Retired marine mechanic cut most of the wires with the intent of rewiring when we got a new motor for it. (He's no longer available to physically help)
- Summation is I have a boat to hook back up where the color codes don't match.
- 2 things he told me to was I could eliminate the auxiliary solenoid where the circuit breaker is, because the Chevy has it's own. Next he said I would need the circuit breaker and yet I see one on this donor motor.

- Keep in mind, I've ONLY started on sorting the wiring. Because the harness from the cabin and the harness from the motor have completely different plugs, he said to use a distribution block to bring those together. I've connected the wires from the cabin to the block using marine grade heat shrink connectors. The only wires from the motor harness that are connected to the block are the RED, and BLACK. I get 12V at all the wire terminals with exception of the ground (black), neutral (white), and purple.
- The starter is brand new. In fact I used it to bump the crank at one point, just by using a battery to ground and the YELLOW/Red wire coming from the solenoid.
The solenoid just spins when I jump the starter terminals with a screwdriver. I get NOTHING using the key switch. I have 12V at the starter and the coil.

I feel as though I'm missing something very fundamentally basic to not be getting anything from the key to start. I DO believe the shifter in in the NEUTRAL position, but I've also tried in several positions just on the outside chance that the the connection might be slightly off. I have no idea if this boat has a neutral safety switch or not. There are no throttle or shift cables connected either.

So I'm going to go with the fact that I've had my head so tightly wrapped up in this that I'm missing something simple. Fresher minds mind have some ideas. This is my first boat with bigger than an outboard, so I'm learning. I have tons of pictures so if you don't see something you think that is important, ask.

 

[Bondo]

- 2 things he told me to was I could eliminate the auxiliary solenoid where the circuit breaker is, because the Chevy has it's own. Next he said I would need the circuit breaker and yet I see one on this donor motor.

Ayuh,...... Yer Bud is wrong,.... Ya still need the slave solenoid, to power the starter's solenoid,......

At the key switch, is there a yellow/ red wire,..??
If so, that's the start circuit,......
It goes from the key switch, through the neutral safety switch, to the slave solenoid, which powers the starter mounted solenoid at the tiny inner terminal,......

Purple is the ignition circuit,.....

 

[Bimmerknut]

I'm not seeing a yellow wire to this ignition switch, Bondo.

 

[Bondo]

Ayuh,.... Put a test light on the white one, 'n see if it powers up when the key is in the start position,.....

 

[Bt Doctur]

guessing its the white wire from the switch, that lug should have a " S"
purple should be coil +power

 

[kenny nunez]

On the back of the instrument panel the oil pressure should be blue and the temperature wire should be brown. The tachometer should be gray.
However I have seen this style of harness on the boat and it is a generic harness, non Mercruiser.
The pink wire on the engine side is probably the ignition/electric choke. Use an ohm meter to check that out just to be sure. You will notice that the engine wires are colored to the respective senders, blue oil, tan temperature. Yellow/red to the boost solenoid like Bondo said.
Are you sure that this engine runs? I hope that the seller ran it for you before you purchased it. What type of ignition does this engine have, electronic or points/condenser.

 

[Bimmerknut]

On the back of the instrument panel the oil pressure should be blue and the temperature wire should be brown. The tachometer should be gray.
However I have seen this style of harness on the boat and it is a generic harness, non Mercruiser.
The pink wire on the engine side is probably the ignition/electric choke. Use an ohm meter to check that out just to be sure. You will notice that the engine wires are colored to the respective senders, blue oil, tan temperature. Yellow/red to the boost solenoid like Bondo said.
Are you sure that this engine runs? I hope that the seller ran it for you before you purchased it. What type of ignition does this engine have, electronic or points/condenser.

Yes, the engine runs. He sent me a video of it running while sitting in his driveway. 5.7 set up for Volvo when removed, with center riser manifolds. Four barrel carb and fresh-water cooling. Also has Volvo crank driven raw water pump. Starts and runs great. Idles smooth. Compression on all cylinders between 150-160. Recently rebuilt. Heat tabs on the heads. The donor boat showed 570 hours but true hours on the rebuild unknown. For a grand I feel it was a good deal.

 

[kenny nunez]

Sounds like you did good. Volvo use Prestolite distributors. If it still has points get a Petronics electronic conversion. If you want to eliminate any heating problems put a through hull sea suction directly to the suction side of the raw water pump and connect the incoming water line from the stern drive to the through hull suction that way you can use the flush out to run the engine. This way it is easier to replace the impeller on the engine than having to split the drive.
Your old Mercruiser engine had a 1 wire Delco alternator, try to adapt it to the new engine. Volvo alternators are VERY expensive and can cause some wiring problems.
Volvo never used a solenoid as a booster but instead had a Bosch style power relay. You will be better off using the original Mercruiser solenoid.
You could even re use the engine harness from the Ford with a little extra wiring.

 

[kenny nunez]

The pump in the Mercruiser drive will NOT have enough flow to cool a fresh water cooling system like this engine has. So be sure to set your engine up like I described.

 

[kenny nunez]

Be sure to connect the shift interrupt wires used on the original engine. The brown wire goes to the negative side of the coil and the black to ground.

 

[Bimmerknut]

Ayuh,.... Put a test light on the white one, 'n see if it powers up when the key is in the start position,.....

That's a NO Bondo. I checked it with a multimeter. Key on or key off that white wire does not get power. Correct me please but isn't white usually a neutral wire? With the key OFF the upper right terminal with the 2 red wires on the key switch is hot. With the key ON BOTH that terminal and the terminal with the blue, purple, and red wires becomes hot.

 

[Bt Doctur]

and when the key is turned further to the "start" position the white wire gets power
rear of switch should be marked "B" "I" , "S" battery, ignition, start

 

[Bt Doctur]

highlight the yellow section, doesent show but the message is the "B" and "I" are reversed, "C" is S"
click to enlarge

 

[Bimmerknut]

Be sure to connect the shift interrupt wires used on the original engine. The brown wire goes to the negative side of the coil and the black to ground.

Couple of things Kenny. GREAT to know about the Pertronix! I actually have the Pertronix II module and coil that goes with it from the other engine. The other engine had a new Pertronix1 in it when I got it. I discovered that with Pertronix1, if you leave the key on you will burn up the module. I read that Pertronix II doesn't do that. So I still have all that and it's barely had any use on it at all. I might be mistaken but I think I also have the alternator from that Ford motor also. The lower end has a brand new water pump and impeller on it. I installed it myself, but I'm sure I'll be asking more about the suction side of the pump when we go to that point. As far as wires, this is my very weakest point of knowledge. I know VERY little about wiring. That said, I would like to have EVERYONE to designate which wires in my pictures they are talking about. The wire harness that comes from the cabin? Those wires are the ones you see attached to the terminal block. The free wires you see in my hand? Those come from the wiring harness coming from the Chevy motor.
as you can see I only have the ground and hot wires connected to both sides of the terminal block. I don't want to get confused with wires from the block and wires from the cabin. Bondo mentioned that I DO need to have that auxiliary solenoid wired in, so I'm going to have to find out how to do that as well. Thanks very much Kenny for the good information. I'm sure I'll have more questions as we go. My main focus is regarding the key switch not responding and why all the sudden the solenoid doesn't engage the starter when the starter is jumpered.

 

[Bimmerknut]

highlight the yellow section, doesent show but the message is the "B" and "I" are reversed, "C" is S"
click to enlarge
View attachment 337429

Thank you BT! I'll take a closer look. I do have this schematic I'm sure as I've created a huge folder of Mercruiser service manual documents in PDF. I will go take a look and post back to you. Thank you sir!

 

[Bimmerknut]

highlight the yellow section, doesent show but the message is the "B" and "I" are reversed, "C" is S"
click to enlarge
View attachment 337429

I see it now. The 2 red and 1 orange wire go to BATT, the purple, blue and red wires go to IGN and the white wire goes to ST. There is no yellow wire as it shows on the diagram. If I'm correct then, that white ST wire is the same wire that I show connected to my terminal block. If that's Start, then that means the the Yellow/Red wire that I'm holding in my hand, that comes from the engine harness, goes to that white wire on the distribution block. Am I correct?

 

[Bimmerknut]

I see it now. The 2 red and 1 orange wire go to BATT, the purple, blue and red wires go to IGN and the white wire goes to ST. There is no yellow wire as it shows on the diagram. If I'm correct then, that white ST wire is the same wire that I show connected to my terminal block. If that's Start, then that means the the Yellow/Red wire that I'm holding in my hand, that comes from the engine harness, goes to that white wire on the distribution block. Am I correct?

UPDATE: Well I made the connection with the Yellow/Red to the White and still no response when turning the key.

 

[nola mike]

. Correct me please but isn't white usually a neutral wire?

There is no neutral wire in DC circuits. Red and black are positive and negative, white can be anything. In AC circuits black or red is hot, white neutral and green is ground

UPDATE: Well I made the connection with the Yellow/Red to the White and still no response when turning the key.

No response where? When you turn the key to "run", you shouldn't get anything. When turned to "start/crank" there should be 12v between that white wire and ground.

I see it now. The 2 red and 1 orange wire go to BATT, the purple, blue and red wires go to IGN and the white wire goes to ST. There is no yellow wire as it shows on the diagram. If I'm correct then, that white ST wire is the same wire that I show connected to my terminal block. If that's Start, then that means the the Yellow/Red wire that I'm holding in my hand, that comes from the engine harness, goes to that white wire on the distribution block. Am I correct?

Yes

 

[Bimmerknut]

There is no neutral wire in DC circuits. Red and black are positive and negative, white can be anything. In AC circuits black or red is hot, white neutral and green is ground

No response where? When you turn the key to "run", you shouldn't get anything. When turned to "start/crank" there should be 12v between that white wire and ground.

Yes

With the key on the ON position, turning it further clockwise didn't not engage the solenoid to engage the starter. Since I cannot be in two places at the same time, testing the white wire while turning the key to start will have to wait until I have another person with me.

 

[Bondo]

That's a NO Bondo. I checked it with a multimeter. Key on or key off that white wire does not get power. Correct me please but isn't white usually a neutral wire? With the key OFF the upper right terminal with the 2 red wires on the key switch is hot. With the key ON BOTH that terminal and the terminal with the blue, purple, and red wires becomes hot.

Ayuh,...... If that white wire don't power up when the key is in the start position, the key switch is bad,.....