1957 Johnson 35hp charging system

diveboss

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i have a 1957 johnson 35 hp with generator charging system that is not working. I had generator tested and seems to be fine. Adjusted polarity, but still not charging battery. Battery shows 12.9v without engine running, and about the same when running, even at high speed.. I’m thinking it will be closer to 14v when under full throttle if it was charging. I’m suspect of the voltage regulator....is there a way to test it? Hard to find a replacement, but I think I’ve found one, but don’t want to buy one if not necessary.
 

racerone

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Have to ask.----How was the generator polarized ?----Is there a fuse in the junction box?
 

diveboss

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Yes, generator was polarized. There are 2 fuses in the junction box and both are covered entirely in tin foil so they are essentially jumped. That’s the way it came. I really haven’t taken them out to check them, or have any idea why that was done.
 

racerone

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Did the generator turn when it was polarized ?---Why not replace the fuses ??
 

F_R

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That junction box is a jumble of wires and connections. And usually a mess of corrosion. And then there is the plug-in connector on the side of the motor. All of those items must be making proper electrical contact, or it won't work.

A simple and quick test is to ground the field (blue) terminal on the generator and run over 2000 RPM. If it charges, the gen is working. And then it's back to the wiring question. BTW, the small fuse is in the field circuit and juice must flow through it to ground the field to make it charge. It is less than 4 Amps, so good connections are a must.

The larger fuse is for the accessories circuit and has nothing to do with gen charging.

Finally, if the regulator has been dunked and is a corroded mess, well what can I say.
 

diveboss

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Yes, disconnected the belt and put power to the generator and runs like an electric motor. Also had it serviced to make sure, and it's all good. Regulator box is actually in pretty good condition as it was mounted in a dry area of the boat. Regulator looks good visually, that's why I was wondering if there was a way to test it. I will try to replace those fuses....20 amp for large fuse and 4 amp for small fuse, correct? not sure why someone would jump those with tin foil, but it's old....boat sat since 1960 indoors, so maybe fuse will help.
The only other variable is the wiring....I wish I could find a new harness that goes to the motor, but doesn't look like they are made any more. Visually looks good, but damn old. Is there a good simple test for the wiring as well?
 

F_R

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An old fashioned auto electric shop could test the regulator. Chances of finding an old fashion auto electric shop are slim to none. But the best way is doing the trouble shooting routine with the whole system. It would require a LOT of typing to explain it all here. Best info would come from a factory service manual (one for gen-equipped electric shift motors)
 

diveboss

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Thanks for the wiring diagram. I will do as much trouble shooting as possible, and if that doesn't work, I can always replace the regulator. My experience with faulty voltage regulators though is that you end up overcharging the battery, instead of not charging the battery....guess it can go either way.
Does anyone know the correct part # for the voltage regulator? The info I have is it's supposed to be part #377001 which was replaced with #381538? The part I can get is actually part #381537 which is supposedly the same as #383609. Are all these part #'s interchangeable?
 

F_R

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Yeah, 377001 was replaced by 380250, which was replaced by 381538. 381537 is the same thing,and includes a cable, used on newer motors (but will work on yours by not using the included cable) 381537 is replaced by 383609. In other words, they are all the same regulator.

Do you really need a generator anyway?
 

diveboss

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I know, good question. I really don't need the damn generator!! I guess I just want everything working as it should. It's a nice old 57 boat and hate wondering if I should have put the damn battery on the charger when I go out. The engines have pull start as well and they typically start first pull, so really no worries about getting stuck.
It's just when the crowd comes around at the dock, you don't want to push the button and have a dead battery!
 

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F_R

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Funny you should mention that. I just got back from a run to jump start my wife's car. She turned the key and bz-z-z-z- dead battery! And yes it does have an alternator. Can happen to anybody.

PS. Of course it was headed into a parking space in a busy lot. Had to shove it out to access the front end.
 
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