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1972 Johnson rectifier voltage drop+ ground issue???

G

greenie

New member
The older 65 hp engine is having trouble cranking. Starter must not be getting enough juice i also replaced both battery cables.

A. The rectifier appears to drop the voltage .3 volts and drop about .5 aps of current. Bad rectifier?

B. I am now able to get the starter to engage the by instead grounding the negative to the motor itself ( not the battery cable).

What do you think?
 
The starter works because if i connect it directly it spins up. Yes, it does appear to be green on the outside of the copper wire coils inside.it spins freely and i lubed it up.
 
You're encountering a voltage drop due to either a loose cable or a tight but dirty cable connection.

Remove "all" of the cable terminals from whatever they're connected to, including the batter terminals themselves.... clean the cable terminal ends thoroughly including the ground at the powerhead and also the components they attach to. Tighten all cables with a wrench or pliers, not your fingers if wing nuts are encountered.
 
Oh well, just because the starter goes up and turns the motor over does not mean that it is in perfect condition !
 
Ok i replaced the positive battery wire all the way to the engine plug as well as the ground wire. Still not engaging flywheel, but seems to be spinning up a little now.next i will replace the bare ground wires that look corroded the braided ones that hook into the engine block directly. I belive it is a ground issue.
 
Hi joe i did what you said, i ended up replacing the ground wite from the batttery to the wire strip on the engine and then replacing the larger powerhead grounds. I also replaced the positive battery cable until the engine wire plug, not quite to the wire strip. I cleaned all connections related to starting the engine and made sure they were tight. Now the starter spins up until it is just below the flywheel. Next i will replace the wire from the solenoid to the key switch unless you had another idea. Thanks.
 
The thing is....... If running jumper wires directly from the battery to the starter results in the starter engaging and cranking the engine properly as you suggest (but don't exactly pinpoint!) in post #3, then the regular engine cables are indeed loose or dirty.......

HOWEVER, as in your post #3, if the bendix gear spins up BUT "does not crank the engine over" (you fail to say one way or the other), then that indicates a faulty electric starter.

To eliminate confusion..... When connecting good known jumper wires directly from the battery to the electric starter, does the electric starter's bendix gear engage the flywheel teeth and crank the engine over normally?

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

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Joe the starter is now cranking the motor if i jump to the contact point of the motor that the positive cable leads to. I know it isnt the positive cable though because they are brand new. There must be just enough corrision beyond that so that it doesnt engage. There is a inline fuse that looks to be using 16 gauge wire rather than the 14 that leads up to it. I will replace that next properly.
 
I remember reading somewhere where you yesterday where you test the neutral safety switch grounding by using it for the negative battery cable and hook the positive battery cable to the starter. Well, the starter turned the motor for a couple seconds, but then there was a lot of smoke and I thought the whole rig was going to explode. I guess it was the switch because now the solenoid won't ground out. Also, I think the power pack is bad because I just installed it and now it is giving me a voltage drop and a quiet ticking noise. :mad: yes I am greenie.
 
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if I understand what you jumpered correctly you just put a hell of a lot of amperage through a circuit designed and built to pick the starter solenoid...the solenoid draws very little current compared to the starter...you have possibly/probably destroyed the neutral switch and the key switch and wiring from the neutral switch to the solenoid...if you have any fuses installed to protect this circuitry you bypassed them...

I will be as tactful as I can to you..admire you for trying to fix it but at this point you need help from someone with a good understanding of dc circuitry and basic marine wiring...
 
I know, i just dont have a lot of money to throw at it. I am a poor college student. My goal is to get the starter to engage the flywheel and by then i should have saved up enough money to pay for the rest and then i can pit it on the boat. It has definately gotten better. The starter is very close to making contact with the flywheel. In all fairness i read on several different places to ground the negative battery cable using the safety switch... Also, this has been very enjoyable for me thus far.
 
Hi racerone, sorry i forgot to mention i did. I cleaned up the magnets with sandpaper and the copper comutator. I think that is actually what go me the last little bit of current i needed. Thank you! So if the starter still isnt turning the flywheel quickly should i buy a new one? I tested the voltage as 11.2 volts going to the starter. By the way, the sparking and clicking noise is actually connected to the "coil".
 
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you have more than one thread on what to me is the same problem...it is my opinion after going back to the start of two threads that you had a very simple problem to start with...either a bad ground to the engine/motor from the battery or a bad starter...who knows what you have now?...we can only be as effective at helping as the accuracy of the info we get and need follow up as we suggest...other than cleaning all connections and jumping from the battery positive to the starter post we try to use logic and troubleshooting instead of swag on electrical problems...parts are expensive and there is some danger involved...
good luck...
 
Engine grounds have been replaced positive cable has been replaced starter to solenoid replaced. Key switch connections cleaned solenoid connections cleaned starter cleaned. Good battery, new solenoid. What exactly would you like to know. I will provide whatever you need.
 
if the starter spins the motor good at at least 350 rom for 5 seconds or so and it does not when using the key then you have a voltage drop somewhere,...the path when doing this is directly from the positive post on the battery through the starter to motor ground to battery negative...there is nothing else in the current path...if you are positive the battery is good and fully charged and there are no resistance in the circuit then address the starter as racerone suggested...it could be border line...if you replace the starter replace the solenoid also..

caution..if the starter turns the engine when jumpering don't let the starter set there and run for long..they are not built for that...
 
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