Strange starting problem, only runs in "start"

[charger_1]

I'm a noob when it comes to boats, this being my first one ever. I have a very good background with electronics, electrical systems, CDI, and automotive engines. This problem, however, has me stumped beyond belief and an exhaustive search on the internet has yielded few clues. I'm hoping someone here might have experienced this or have some insight on the matter...

I purchased this motor just a few days ago, previous owner assured me that it had been run this year. My 69 Johnson 115HP V4 outboard will start, and run just fine, so long as you keep the ignition switch in the "start" position (and allow the starter to keep cranking even after the bendex drops out). As soon as you release the switch to the "run" position, it kills immediately. There is no "kill" switch. The electronic shift is in the neutral position.

Here is what I've done/tried:

Checked all wires to the ignition switch, all correct

Checked the switch itself, works perfectly

Manually pulled the wire from the ignition switch from the solenoid while holding the ignition switch in the "start" position... kills immediately.

Manually pulled the heavy gauge wire from the starter while holding the ignition switch in the "start" position... kills immediately.

Bypassed the (forgive the term if wrong) rotation sense module that provides power to the ignition module when the engine rotates... no difference

Double and triple checked the wires to the starter solenoid, and terminal strip

Verified that the solenoid is the "isolated" type

Checked all known grounding points for secure, clean connection

I'm on a HUGE learning curve with this motor, and have learned a lot regarding outboard motors in the process. This phenomenon has me stumped, along with a few other seasoned boaters I've spoken with. One suggested a fuel cut-off solenoid, but I see none. Another suggested the ignition module, but would it run at all if so? One suggested a water sensor, but all information I find suggests there is none. Yet another suggested some sort of interlock with the mechanical advance, but I don't see anything like this in exploded-views of the motor found online.

Tomorrow I am going to isolate the stator coils, and the voltage regulator, just to basically eliminate anything other than the ignition module and the starter circuit..

Am I on the right track? Should I be looking elsewhere? Any help or thoughts would be greatly appreciated.

Thanks!

 

[tashasdaddy]

Re: Strange starting problem, only runs in "start"

bad ignition switch, or mis-wired. shorted harness, disconnect the black/yellow tracer wire, this is the kill wire to motor. 1969 is an electric shift motor, if not mistaken, wiring diagram may be different, this is standard wiring diagram for all motors.

 

[F_R]

Re: Strange starting problem, only runs in "start"

Certainly sounds like a bad ignition switch to me. What you need to do is check the voltage at the purple wire that feeds the ignition safety circuit when the key is in the "run" position.

You already said you tried bypassing that safety circuit so I won't suggest that. Um...exactly how did you bypass it? Bypassing it is one of the standard troubleshooting tests.

Anyhoo, if you don't have adequate voltage at the purple wire, it won't run anyway. We know that the wire itself is ok because it runs when the key is on "start". Gotta be low voltage in the "run" position. (Gotta be---as in "probably")

ALL of the stack of purple wires are on the "ign" post of the key switch, right?

How it works: The ignition switch sends voltage to the purple wires, in both the "start" and "run" positions. One of those purple wires goes back to the ignition safety circuit. There are two yellow wires, also going to the safety circuit, and they come from the alternator. When the engine is rotating, the alternator is putting out, and the safety circuit "sees" that and turns on. When the safety circuit is turned on, it completes the circuit between the purple wire and the purple/black stripe wire that feeds the pulse pack, and the motor can run.

Purpose of the safety circuit: It is possible for the pulse pack to produce a spark merely by turning the key on, without actually cranking the motor. There were incidents where accidents happened from accidental starting that way, so the safety circuit was added. Now the driver must intentionally be cranking the motor before the safety circuit sends voltage to the pulse pack.

Hope this helps you figure it out. Your experience should be a HUGE help.

 

[jonesg]

Re: Strange starting problem, only runs in "start"

Not to confuse matters, can't he just disconnect the harness and jump start it at the solenoid? If it runs its very likely the ig switch.

On later engines (mine is 1994) 12v is directed to the power pack when the starter is turning via the yellow/red stripe wire, this wire is only energized during cranking so the PP see's a good 12v supply.

If it runs when cranking only then the problem is the charge coil in the stator.

Ignition switch sounds a lot cheaper though.

 

[charger_1]

Re: Strange starting problem, only runs in "start"

Tashasdaddy:

Mine is different. I have the "black plug" for my remote, and don't have any black/yellow wires what so ever. I don't have any kill switch of any kind. The ignition switch is a basic 3 pole, you have your +12V in, run, and start. The only wire from the start goes straight to the solenoid coil terminal 1. Solenoid coil terminal 2 has a single wire as well that goes to the other side of the motor to ground to the block through the start position switch. That's it for the start circuit.

F_R:

The ignition switch has a purple wire that goes to the terminal strip atop the PP. Voltage measured at the terminal strip confirms 12V there. Two additional wires leave from the "run" position, one goes to the HOT light (which in turn goes to the terminal strip, then to the temp sensor, then to ground) and another that goes to the remote for the electric shift.

I bypassed the safety by removing the wire from the PP that connected to the terminal the output of the safety was connected to. I then placed that PP wire under the 12V (purple) terminal screw, to ensure that wasn't the cause of the problem. It had no effect, same symptoms.

The overall design of the circuitry is so simple, it really doesn't make much sense that the starter has to be physically turning in order for the engine to continue running.

When I return home from work, I am going to disconnect the stator wires from everything, since they only go to the voltage regulator and the safety module. I'm going to just run the PP to 12V only and see what happens from there. It's almost as if something is either finding a ground loop through the starter, or there is a frequency feedback being generated that "knocks out" the PP. That is, unless there is a chance that something is going to fry in the process!

What does everyone think?

 

[charger_1]

Re: Strange starting problem, only runs in "start"

I have an interesting update...

After obtaining a repair manual at the local library and painstakenly tracing EVERYTHING, I noticed that the clipper circuit was missing a wire as was the pulse pack. I gave up for the night, since any more work would seriously disturb the neighbors. For the heck of it, I checked the schematic for a 72 100 and 125hp Johnson.. They match up with what I've been finding on my motor! So I go out again and look at the tag on the motor. The lower unit has the tag for the 69 115hp, and the hood is also 115hp, 69 style. The mounting bolts on the power head, however, have paint missing. I'm thinking that the power head was at one time replaced in this motor!

So, with this information, I discover that there is a circuit in the 72 that is attached to the anti-reverse spring. I haven't yet verified if that is indeed there, but it would make sense now. Runs in "start" but not in "run".

So, is there any way to determine what year and size power head is on this thing?

I should add, the voltage regulator tests bad and there is no output on the clipper circuit, but after looking at the schematic on the 72, it doesn't seem like the clipper circuit would have an output at all, since it doesn't feed the pulse pack power as the 69 would.

Thoughts?

 

[F_R]

Re: Strange starting problem, only runs in "start"

The anti-reverse spring doesn't do a darn thing as long as the crankshaft is rotating in the correct direction. Yes, it grounds out the pulse pack if the engine tries to run backwards (yes, it can run backwards). So I fail to see how that could be tied into the problem at hand. However, if it is worn out and dancing around loose in there it certainly could cause erratic ignition.

Don't confuse a clipper circuit with an igniton safety circuit. Totally different things and different purposes. A clipper circuit "clips" high voltage spikes to a safe level so they don't ruin the pulse pack.

I guess your first chore is to figure out exactly what you are working on, right? But by your report on changing the wiring to eliminate the ignition safety circuit, it sounds like a '69. Dang if I know.

EDIT: OK after thinking about the project awhile, I figure we gotta use some logic here. I know just enough about electronics to be dangerous, but as I understand it, the pulse pack has some kind of oscillator circuit inside to change DC to AC so it can be amplified up to 300 volts. That's all sealed inside, so few of us mortals really know how it does it. But I still say you have an input voltage problem. That input voltage normally is about 12 volts when not running or cranking. When cranking, the voltage will drop to around 11 volts, depending on the battery, starter and stuff. But when it starts, the alternator starts putting out and the input voltage is regulated to about 14.5 volts.

Realizing that, it is obvious that your pulse pack is working at 11 volts (while cranking), but quits working at whatever the running voltage is. I suppose that could mean a defective pulse pack, but probably is not. I would rather think it is related to that bad voltage regulator that you admit you have.

I think you need to get an accurate voltage reading at the pulse pack input, while cranking and when it conks out. If you have a digital voltmeter, it may not be able to react fast enough to see it.

I suppose, in additon to that, maybe it is getting an unrectified AC from the alternator?? Now we are getting far out in theory.

You mentioned disconnecting the alternator completely. Perhaps that is a good idea, see if it runs then.

I'm going back to bed now. It's 3:24 AM.

 

[boobie]

Re: Strange starting problem, only runs in "start"

The way I used to do it was start at the left side of the terminal board and count the screw terminals. At that time I would put a spade terminal jumper wire between terminals # 7 and #9. This would by pass the the charging system,safety circuit and all. All you were dealing with then was the ignition circuit. Then turn on the key and see if you have 12 volts going into the power pack. If you do, then crank it over and see what happens. If you don't have the 12volts there that is your prob. I still think you either have a bad ign sw or something in the purple wire not feeding the pp it's voltage. One dumb question. Are there any wires coming from the starter solenoid with maybe a diode in the wire going to either terminal 7 or 9 ?

 

[charger_1]

Re: Strange starting problem, only runs in "start"

The motor runs!

I decided to use the 72 schematic to ensure the engine was wired correctly. The reasoning behind this decision came from the lack of a wire on both the clipper circuit and the pulse pack, which went along with the 72 schematic.

After doing this, I also decided to pull the flywheel off and make sure the pickup coil was properly gapped. This is what I found:

 

[charger_1]

Re: Strange starting problem, only runs in "start"

I took it completely apart, cleaned it, and carefully inspected the wires. Under each clamp was a bare spot. I ended up replacing all the wires by soldering and double heat-shrinking every connection made. This is the end result:

 

[charger_1]

Re: Strange starting problem, only runs in "start"

After putting in the pickup assembly back in and regapping the pickup coil to the proper specs, I cleaned the rotor and put it all back together. Still no run though. I started looking at the wires from the plug to the pulse pack that this all connected to, and found that one of those wires were cracked in several places and had just a thread of wire connecting everything, just enough to get a DVM to read, but not enough to carry any current. I replaced that wire in the same manner, and she fired right up!

Thank you all for your assistance. Definitely a worth-while forum. I've learned a lot about these motors in the process, and look forward to doing it all over again. Definitely know how to identify symptoms now!

 

[HighTrim]

Re: Strange starting problem, only runs in "start"

Good work and interesting thread....thanks for the update.