1969 McCulloch Outboard Blowing Fuse, Won't Turn Over Unless Solenoid Jumped

monkbonk

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I have a 69 Sears boat with a 75hp McCulloch engine. I had it running a while back, but that was after replacing the 14 amp inline fuse and jumping the solenoid. Thought I had a bad ignition switch, so I replaced that. Then I replaced the starter solenoid. I have a short somewhere and have noticed two wires that aren't connected at all in the main harness. One light blue wire looks to come from the coil, but the PO cut it midways back. Another is medium sized white wire that's cut. Haven't traced it yet.

I'm hoping that someone has a wiring diagram for one of these boats out there? Right now, all it is doing is blowing that 14 amp fuse. As soon as I put one in, it sparks (while I am connecting the fuse holder!).
 

F_R

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I have no clue whether or not this diagram applies to your motor. But if it does, the 14A fuse is in the alternator/rectifier circuit and has nothing whatsoever to do with starting the motor. But if it blows, the rectifier is probably blown.
 

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monkbonk

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Thanks for the diagram. I know that if the fuse isn't in place, I do not get any ignition spark.
 

F_R

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If that is true, then this is not the correct diagram, or your motor is wired wrong.
 

monkbonk

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I wonder if my starter solenoid is wired correctly. I have the positive cable on either side correct, but there are two smaller terminals on the front of the solenoid. I have a wire running to one (nearer the bat power), but the other terminal has no wire attached. I assume the attached wire runs from the ignition switch and is the "trip" wire. I was wondering if I should have another wire attached to that empty lug terminal?

I have a ground wire that's attached to the body of the starter solenoid (where it mounts to the outboard casing).
 

F_R

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Well there ya go. Now the question remains, is it the correct diagram, OR is it wired wrong. I'll make an educated guess and say it is wired wrong in the sense that it has the wrong solenoid installed. Furthermore, now we have to guess do you have an OMC solenoid, or do you have a solenoid from the auto parts store?

Do you have a voltmeter (multimeter) and do you know how to use it? If you do, the mystery can be solved in minutes. Otherwise, I'm going to go on the assumption that you are a complete Dummy concerning electrical circuits (Sorry 'bout that).

What I want you to do is first find out for us what kind of solenoid you have. I want you to disconnect all the wires from it. Now I want you to take a couple of pieces of wire and connect the solenoid mounting bracket to the (-) terminal of the battery. Then use the other piece of wire to connect the (+) battery terminal to one of the other small terminals on the solenoid. Does the solenoid click, yes or no? If no, move the wire to the other small terminal on the solenoid. Does the solenoid click, yes or no? If either of these test yes, you have a car solenoid. If neither prove yes, move on to the following test----

Connect the (-) battery terminal to one of the small posts on the solenoid. Connect the (+) battery terminal to the other small terminal on the solenoid. Does the solenoid click, yes or no? If yes, you have an OMC solenoid.

I've already typed more words than I care to, if you aren't willing to do the tests exactly as I described. But if you do them exactly as described, come back with the exact test results and I'll tell you how to proceed from there.
 

monkbonk

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I believe I have a car battery solenoid. The solenoid clicks when the ground is connected to the body of the solenoid and not the little 2nd lug. I have three of these things (two are new), and all behave the same.

The wire that continuously blows the inline fuse goes to the alternator rectifier. According to the above diagram, it should also run to the starter solenoid?

Perhaps I need a new rectifier. Looks like a Johnson 3 wire will work.
 
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F_R

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Yes, that is a car solenoid. No problem, ground it so it works and run it, and ignore the second small terminal.

Electricity flows from the alternator rectifier to the fuse, through the fuse, and to the junction with the battery cable at the solenoid. That is the ONLY current the fuse carries---charging current from the alternator to the battery (+) cable. The fuse does not feed the starting or ignition system in any way. If it blows, the rectifier is burned out. Is it a silicone rectifier or a selenium rectifier? Selenium one looks like a stack of crackers.
 

monkbonk

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Silicone rectifier. I'm going to trouble shoot some more. I need to verify whether or not I am getting spark without that fuse in place. I have two wires from my stator that feed into the rectifier and then that fused red wire.

I can see the stator if I peek below the flywheel. It looks to be in good condition from that vantage point. No burnt spots.
 

F_R

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Yep, that's the normal alternator hookup. Used to be you could get those rectifiers on the cheap from Radio Shack. I think they closed all or most of their stores now (??).
 

monkbonk

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The rectifier seems to have fixed it. I no longer blow my 14 amp fuse, and the boat is running again.
 
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