1975 75 hp Stinger no spark

[edquade]

Hello folks,

I had my boat out on the lake today, started great, ran great at all rpms from trolling to wide open. As I was trolling it was as if somebody had shut the key off. No spit and sputter just plain quit, and then I could not get it restarted. Battery is charged, plenty of gas, its getting gas up to the carbs. I did however, pull each spark plug off and tried seeing if any spark would jump to a ground and I did not see any spark whatsoever. Before today it had a very strong spark on all cylinders. Would this be a power pack problem or possibly coils?

Sorry if I am asking questions you've heard a million times, I'm newer to working on outboards myself.

Thanks in advance for any help you're willing to offer!

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Happened to me not long ago on an 82, it was the safety lanyard line, the switch was shorting to ground now and again. It could be that or your ignition switch failing too.
Disconnect the yellow/black wire from the powerpack and retest

 

[edquade]

Re: 1975 75 hp Stinger no spark

Thank you! I will try that. What exactly does this safety lanyard line do? And if disconnecting the yellow/black wire from the powerpack works, what would I need to replace?

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Safety lanyard line is standard on some models or installed on some others as aftermarket.
Its normally a red bungy cord that you attach to yourself and the other end to the control box, so if you go for a fly from the drivers-seat when out boating the motor will cut instantly.
When the cord is yanked out of its holder the switch turns on and the kill circuit (black/yellow wire) is thus completed to ground, killing all spark.
The black/yellow wire also gets connected to ground through the key switch. Any shorting to ground along the wire to the control or in the key switch will then cause that wire to ground out killing all spark until it is disconnected.
When you turn the switch to off it grounds this yellow/black wire and thus stopping spark.
So its useful to check this circuit first in any non spark troubleshooting

 

[edquade]

Re: 1975 75 hp Stinger no spark

Alrighty, I disconnected the yellow/black wire from the powerpack and I still have no spark. Where should I look now? Does that mean my ignition switch has gone bad? The troubleshooting section in my repair manual doesn't appear to address this type of situation. Thanks for the help!

 

[edquade]

Re: 1975 75 hp Stinger no spark

Also, a quick rundown of what has been replaced since I purchased this boat in June:
1) New Battery
2) Impeller/water pump kit
3) Starter
4) Starter Solenoid
5) Battery cables
6) Head gasket
7) Exhaust manifold gaskets

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Sounds like your ignition switch is ok
Theres a checklist to work through. Its in this troubleshooter manual so flick through the pages til it shows your engine model, it will then give you a step by step instructions on how to isolate it.
ISSUU - CDI Electronics Practical Outboard Ignition Troubleshooting by CDI Electronics

Id also check your stator wires havent become shorted to ground. Sometimes they get bare and corrode leading to a leak to a ground or they crack apart which results in no spark/ Using a $10 mulltimeter you can check if the are shorting to ground or disjoined

 

[edquade]

Re: 1975 75 hp Stinger no spark

I started going through that troubleshooting checklist. Still can't get spark after removing the two yellow rectifier wires. I did notice the red wire going to the rectifier is all burnt looking and the insulation is peeling off of it. However, holding it out so the red wire isn't grounding I still can't get spark. Would this mean the rectifier is bad, or just the red wire, or do I need to keep looking? I can't tell that any stator wires are bad. I'd hate to just start replacing parts. Any help is welcomed gratefully!

 

[edquade]

Re: 1975 75 hp Stinger no spark

I've ruled out the kill switch/ignition switch. I don't believe it would be the coils. The wires going to the stator appear to be fine yet.

Would a bad rectifier or bad red (power?) wire to the rectifier cause zero spark on all 3 cylinders?

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Have you tried ohmn testing those stator wires?
A bad rectifier can burn out a stator. Thats where your spark power is generated so its the first thing to test.
After that ohmn test, test the timing base wires and if they all check out and you are sure its not the killwire and switch then your choice is to either make or buy a dva tester to test the powerpack and stator and timer base more thoroughly or take the gamble and buy a powerpack

 

[edquade]

Re: 1975 75 hp Stinger no spark

All three stator wires tested to the stator ground are giving me zero ohms of resistance. Is this the proper way to test them? I just purchased the multimeter so this is all new to me.

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

I suppose you mean you a getting infinity resistance to ground, the same as if you hold the two leads apart in the air?
Zero resistance is basically a perfect conducting circuit so is not what you want from stator to ground- ie a very low reading such as 1 ohmns is almost a perfect circuit, zero would be a perfect circuit to ground. Your multimeter is probably showing a - or nil to indicate infinity.... which is what you want for that test
To test the stator and timing base track your motor down again on that trouble shooter and it will tell you which two pins to touch the leads to in the connectors coming from the stator. Record those results and compare them to what value they should be as given in the troubleshooter.
The troubleshooter will say something like

Stator brown to brown/yellow 400-550 ohmns.
On each stator connector use your leads with one touching the pin that goes to the brown wire and the other touching the pin that joins to the brown/yellow lead then see what value you get and check its within the value ie 400-550 ohmns

 

[edquade]

Re: 1975 75 hp Stinger no spark

I guess my multimeter is reading slightly over zero ohms on the stator wires. Its not digital and times 1K so its hard to get exact readings. I was testing from the screws in the power pack to the common ground.

Also the troubleshooting guide wire colors aren't the same as my engine. Which is actually a 1977, (my bad). So I'm a little clueless there. The only similar colors are brown tested to brown/yellow which should be 400-600 ohms, whereas I have brown tested to brown/orange that tests about 800 ohms. Is that evidence enough that stators are bad?

I do plan on replacing the rectifier since the red wire is all burnt up and there's nowhere to attach a new wire in its place.

Thank you so much for your help and patience!

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Stators a expensive you should try and get a cheap multimeter, they a like $10 so you can be more certain of the result.
Did you find any black/white wires which are from the timing base?
If your meter is analogue you might be able to get some peak voltage readings on the stator as you crank the engine.
Is it cranking at a decent speed? Or is the starter only turning it slowly?

 

[edquade]

Re: 1975 75 hp Stinger no spark

I've got a cheap multimeter, but the only resistance measurement is ohms x1000. It appears that the needle is slightly above zero when I test the stator wires which appear to all be white with a black stripe, right below those three wires there is a black wire with a white stripe. On the left side of the powerpack there's the brown wire and brown/orange wire that tested 800 ohms.

I will get somebody to crank it over while I check voltage. It is cranking plenty fast. Basically everything from the battery to the starter is new, (cables etc, solenoid).

 

[edquade]

Re: 1975 75 hp Stinger no spark

To clarify my powerpack wire colors are starting on the left side going down.
Ignition coil 1 orange
Ignition coil 2 orange
Ignition coil 3 orange
Charge coil brown
Charge coil brown/yellow
Ignition switch black/yellow

Right side top going down:

vacant
sensor 1 white/black
sensor 2 white/black
sensor 3 white/black
sensor common black/white
ground lead black

The only wires I got a higher ohm reading was between the two charge coil wires, brown to brown/orange and that read 800 ohms.

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

I dont know if your meter will pick up 10-20 ohmns if it only does x1000 but if it does then it sounds like your timer base is broken or the wires to it are. They often corrode internally so you just replace them.
If your timer base has gone it can blow your powerpack after a while as the charge sent to the powepack doesnt get triggered to release.
So if you a happy that your reading from the timerbase wires are not reading then start looking into that unit

 

[edquade]

Re: 1975 75 hp Stinger no spark

Okay, I got ahold of a digital multimeter now. My charge coil wires are actually reading a resistance of 652 (my service manual says 630 ohms +-50 ohms), so that appears to be good. The sensor wires are reading 8 ohms (book says 8.5 ohms +-1.0 ohms) so those also appear to be good. I haven't aquired a helper to crank it over to measure peak voltage yet. But so far the resistance readings apppear to be good.

I talked with my local OMC mechanic, he said that the burnt up red wire on the rectifier grounding out may have caused voltage to be backfeeding and possibly going through the terminal block/powerpack which could have fried the powerpack itself (or as he calls it the CD pack). He advised me to check the resistance readings again and if those appear fine to try replacing the CD pack. Does this sound like it may be the case to you?

Once again, thank you so much for the help. I've been learning a lot about outboards working on this motor, with the knowledge and assistance of folks like you.

 

[Bosunsmate]

Re: 1975 75 hp Stinger no spark

Hi
You could do as he said, but of course its not him who pays if the powerpack is actually ok. You cant normally return electronic parts


You could when cranking measure the peak voltage on the wires out of the powerpack, if they are low then pull the stator wires and check those.
If those are fine then stator is ok and the powerpack is bad, but if they arent fine then the stator is bad or both.

 

[edquade]

Re: 1975 75 hp Stinger no spark

So I would be holding the positive lead on the orange wires going to the coil and the negative lead on any ground correct? And I'd be looking for a peak voltage reading of 150 volts? Also, just to clarify the stator wires are the three white/black wires that the service manual calls sensor wires?