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Repeated power pack failure

S

Scod

Member
Hi guys, I have a 1982 Johnson 140. I blew a power pack, replaced it with a second hand one, this new power pack didn't resolve the issue and I found the timer base was faulty. In the meantime I bought another second hand power pack and installed it with the timer base and it ran fine for two trips out. I took the heads off, reinstalled them and sure enough I've lost spark to one cylinder again.

All three power packs have failed on the same side, the first two on the top cylinder and the last one has occasional spark on the bottom cylinder. I swapped the faulty pack with the one on the other side of the motor to confirm the power pack is faulty. The fault moved to the other side of the motor.

I disconnected the kill wire and connected my multimeter. It reads 0.00 volts with the key in the off position, 0.00 volts with the key in the on position, but as I turn the key on or off I can get a little reading up to 0.02 volts. Is this enough to kill a pack?

Or could the first two packs have been killed by the faulty timer base? I have a new (second hand) power pack ready to go but don't want to kill it. I don't have a DVA meter.

Thanks in advance.
 
Definately replace the ignition switch but my guess is the stator is cooking the PP. What kind of battery are you using will cause the stator to get hot and fail internally. The trigger either works or it dont. Get a DVA and test the stator and trigger if you replace the stator it is wise to put in a new rectifier/reg at the same time with a good lead acid type marine battery. A maintenance free or closed cell battery is the most common cause of ignition failure due to the stator overheating and failing internally. It is easy to swap parts but until you do a proper diagnostic it can get real expensive. A DVA can save you alot of money in the long run.
 
Yep, the diagnostics is always the challenge. I'm thinking about running the kill wires to a dedicated switch to turn off the motor, keeping it away from any other wiring that could affect it. Your thoughts?

Also the earth wire for the pack that goes on the pack mounting bolt behind the pack, if that connection is bad could it blow a pack? One of the holes has a dodgy thread so i moved the earth to the other bolt but now I'm thinking the block is probably painted there and might be giving me a bad connection. Possible?
 
cleaning connectors and grounds is preventive maint and should be done anyways periodically. Especially if your having electrical issues you want to make sure the wiring is good to properly troubleshoot components. One of those kill buttons mounted on the engine could never hurt you can always just leave it there once you get the ignition sorted out. Makes it nice you can kill the engine without going forward if you get a big one on when trolling.
 
but my guess is the stator is cooking the PP.
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Nope cant do it. If stator damaged pack it would be the capacitor and if its damaged you will lose both cylinders....
The trigger either works or it dont.
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Nope ....the way OMC trigger is designed it can come and go..very common problem on V-6 motors as heat related.
If it is constantly failing on same cylinder the coil is at fault as it inducing a kickback into PP damaging SCR on that circuit/cylinder.
 
Another consideration with triggers is that since the wires are moving, they can get damaged. This will be an intermittent failure, not the case for you but it is important to check triggers in all throttle positions. Any ground requires a star washer between the block and the wire, this will give you the insured continuity to stay safe. Grounds are critical and often ignored. Coat over them with liquid tape after the threads Have been anti seized.
I agree that both cylinders would drop, that's cast in stone. If the motor is real nice, great compression, your gonna keep it.....I would go new coils, packs, stator.....you already have the new trigger. Or was that used too?
For me and my personal motor, it gets done completely. I recommend the same for my customers, but some want bandaid jobs.
 
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This is a V4,right? If the stator is to blame it would snap the packs' capacitor which stores charge for both cylinders for independent discharge when triggered. Between triggers it is re-energized. Power packs are often to blame but the cause may run deeper,and often does......may not show up right away,but wait until the last minute to head in before the storm hits, been there brother.
 
There's a fair bit to go through, I think I'm probably better off taking it in to have a man look at it. It could cost me more in time spent and unnecessary part ordering if I try to do it myself. I'm sure if I pay someone it'll turn out to be a bad coil or something equally simple
 
Shops are expensive as they have a large overhead. I work under the shade of poplar trees and balsams, my rates are pretty good and my work is even better. Trouble is in northern MN, the boating season is only about 7 months for the most hardy, so I sell firewood in the fall and winter. If the coil spanked the pack, you will need both items and I might suspect the other coils as well. If operating conditions were such that one coil is sick, then.........
 
Living the dream Timguy. I actually have a new coil ready to go. Also a powerpack, I just haven't fitted them because I don't want to kill them if the problem comes from elsewhere. I've spoken to a shop who are happy to run the diagnostics for me and tell me where the fault is and I'll replace the parts myself. There's just too many possibilities and if I get it wrong and blow another pack I might as well have paid the workshop.

All my problems started after the starter solenoid bracket came loose and the starter solenoid turned in the bracket, earthed out against the block and blew. This killed the timer base. Could it affect anything else? If the starter solenoid is the wrong part could it be the culprit? It came from my mates motor, he has a 1977 model. Some parts are interchangeable, some are not.
 
Okay, solenoid is okay to use. Have the shop test stator with ohms and DVA. The DVA measures pulses that won't show up on a regular multi meter. Your rectifier is likely bad if there was a short. They are pretty inexpensive. There should be a little in line fuse too, search it out, it is on a single red wire I think on your motor. Test that. Coils (spark) can be easily tested too look for cracks or melting. Used are okay on these, Tim's Outboard Hackensack MN, best in the Midwest. Just bought a used Powerhead, 400 bucks.......golden.....came wrapped in bath towels. Put them in the washing machine, my wife thought they were new towels when she got home.
 
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