'75 Stringer intermittant no crank situation?

Boomyal

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Not sure if this should have gone in the Electrical Forum but being as it near stock OMC I thought I would post it here. Over several summer play trips, when I shut off the motor, it fails to turn over on restart. First thought was dirty battery terminals so I removed them an wire brushed them while tied to a dock. It cranked right over after that so I thought I had found the culprit. This happened several other times on different trips and I would go back, twist the cable eyes and re-tighten on the clamp nuts. Sometimes I would have to go back and fiddle with them a couple of times before the motor would crank over.

When this would occur, I would turn the key to ignition and all the gauges would respond normally. Moving to start, I would never even get a solenoid click.

Fast forward to yesterday's trip. Out in the middle of the river I shut down for everyone to jump in. On restart it would not even click (routine). I once again checked the battery cables and all seemed well. What I discovered this time was that while the no crank condition existed my outdrive would raise and lower. As the tilt motor requires a fair amount of amps, this discovery ruled out that the battery connections were ever my problem. Besides that, I have experienced corroded cables many time in my life and you would always, at least get a solenoid click.

The only deviation from stock, in the wiring department is that years ago I installed a permanent magnet mini starter that has it's own solenoid. So the original OMC starter solenoid now just acts a a switch to trigger the built-in starter solenoid.

My goal is to figure out the points that this situation could occur in; something that I could trace down while on the water. I have never been able to duplicate this issue while on the trailer.
 

bruceb58

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I would bypass your neutral start switch in your control when this happens.
 

Boomyal

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I would bypass your neutral start switch in your control when this happens.

I thought about doing that Bruce, as that was one of the likely spots. But I would have to disassemble the whole shifter assembly to get to the leads and that would be cumbersome out on the water.. I suppose another option would be to cut the two wire lead going into the shifter box and twist them together. I hate to have to do that, though.

Other possible areas of problems would be the continuity thru one of the two big connecter/fuse plugs. I assume that the signal from the ignition switch has to go thru one of those plugs to get to the solenoid?
 
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bruceb58

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Other possible areas of problems would be the continuity thru one of the two big connecter/fuse plugs. I assume that the signal from the ignition switch has to go thru one of those plugs to get to the solenoid?
That's definitely a possibility. Pull the plug apart and inspect it. See if there is corrosion there.

So when you try to crank your engine and the starter doesn't operate, can you hear that solenoid that you left on there actuating? If it does, it's not the neutral safety switch.
 

Boomyal

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That's definitely a possibility. Pull the plug apart and inspect it. See if there is corrosion there.

So when you try to crank your engine and the starter doesn't operate, can you hear that solenoid that you left on there actuating? If it does, it's not the neutral safety switch.

I could not hear the solenoid click from the helm. As such, I made the assumption that it was not clicking. In retrospect, to be sure, I should have had someone turn the key while I went back and stuck my ear under the motor cover.

I will have to see if I can identify the start wire going from the connector/fuse plug, to the original starter solenoid. Then I can disconnect it so I can see the specific pin and socket for that wire. After I clean the terminals, both male and female, do your think I should put some dielectric grease on the pins?

I will still take the throttle control apart and check out the switch. As I recall, it is just one of those little micro switches.I know those kinds of switches can go out and mine is now 36 years old, but so are the original starter and tilt solenoids.

What is the likelihood that there is a problem in the ignition switch, itself? It certainly works consistently in the run position.
 
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bruceb58

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On an electric shift control, there is less to go wrong compared to a mechanical shift. I have had cases where the control was getting sloppy and not allowing the micro switch to engage properly while in neutral because of all the slop that developed. Obvioslly, since you aren't operating a shift cable too, the control develops less slop in it over the years.
 

Boomyal

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On an electric shift control, there is less to go wrong compared to a mechanical shift. I have had cases where the control was getting sloppy and not allowing the micro switch to engage properly while in neutral because of all the slop that developed. Obvioslly, since you aren't operating a shift cable too, the control develops less slop in it over the years.

I forgot to re-emphasize that my '75 was converted to a hydro-mechanical drive in '79. Mentioning that makes me wonder how they wired in the neutral safety switch. I am sure that they must have tied into wires in the original harness?
 

bruceb58

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I would think so. Like I said, I have had console controls wear out over the years where the neutral safety switch wasn't getting closed properly in neutral.
 

Boomyal

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Is the neutral safety switch a ground switch or a positive switch? I followed the switch lead (from the control box) back into the side panel and then back up under the dash. There is a rubber coated male/female connector about 16" away from the box. I will be able to test the continuity of the switch from that connector and eventually get a spare pigtail so that on the water I could unplug the connector and plug it into my shunt connector. If I am in a no start condition, this will isolate the switch from the circuit and verify whether or not the switch is the culprit.

In the meantime I want to follow that wire back thru the fuse/plug so that I will know where to probe if the switch is not the problem. I could probe on either side of the fuse/connector plug then on down to the solenoid, if I have to.

Right now I want to know if there is power going thru the NSS, or is it just a ground. Either way, I assume the switch is closed on start and open when you are in gear.
 

bruceb58

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The switch is just inline between the start terminal of the ignition switch and your "slave" solenoid. You will need 2 pigtails to test it.
 

Boomyal

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The switch is just inline between the start terminal of the ignition switch and your "slave" solenoid. You will need 2 pigtails to test it.

I take it then the the control box switch is a power interrupt switch. It is not on the ground circuit? As for pigtails, I was going to buy an accessory male/female pin plug and connect the two wires coming off of it. Then when the 'no start' condition occurs, I would unplug the lead from the box and connect my looped accessory plug to the plug coming from the ignition switch and going back to the fuse/plug connection on the back of the engine.
 

bruceb58

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LOL...I think you are describing what I am thinking!

No...there is no ground involved.
 

Boomyal

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LOL...I think you are describing what I am thinking!

No...there is no ground involved.

Hmmmm? I'll have to cogitate on that. I was thinking that there were two wires, one positive, one negative. But now that I think about it, it is like a lamp switch. You just cut the positive wire and insert the switch between the two ends. OK, Got it!
 

bruceb58

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Hmmmm? I'll have to cogitate on that. I was thinking that there were two wires, one positive, one negative. But now that I think about it, it is like a lamp switch. You just cut the positive wire and insert the switch between the two ends. OK, Got it!

That's all the NSS does. It disconnects the start switch to your slave solenoid.
 

Boomyal

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That's all the NSS does. It disconnects the start switch to your slave solenoid.

Will proceed with understanding the wiring and with understanding future breakdown diagnosis, accordingly.
 

Boomyal

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Although this will have to wait until next boating season, I got my Neutral Safety Switch shunt today and tie wrapped it to the lead coming from the ignition switch. Now if I have a no crank episode, I can reel the lead out of side panel, disconnect the NSS and plug the lead into my shunt. Beyond that, I located and confirmed the terminal on the original OMC starter solenoid. So, if I encounter no crank and the shunt does not remedy it, I can quickly take my onboard test light and chech the for power at the solenoid terminal.

At the same time, I have identified the start terminal on the back of the ignition switch. I will be able to quickly test that terminal to see if it has juice. This just would have been impossible to understand, then test all these things out on the water without having previously developed an understanding of all the whys and wherefores.
 
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