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Two failed power packs in less tha 15 hrs. running time!??

A

auxarcsman

New member
Hello. I could use some input and would greatly appreciate any as to why I have had two failed power packs in less that 15 hrs. running time!

First, let me say that I recently purchased a 2001 Bennington pontoon with a 50 hp Johnson (J50PLSIB). I took it to my local boat shop and had it gone over to make sure it was lake worthy. They put a seal kit in the lower unit and adjusted the carburetors and said it was good to go.

The second outing of a total of about six hours of running time I tried to increase the throttle only to have the motor fall flat on it's face and start shaking violently. After researching this I found that it was either my heat sensor or power pack that was the culprit. The motor never sounded and alarm for heating up and the self check performed as it should when starting so I ruled out the heat sensor as the problem and replaced the power pack which fixed the issue for a short time.

Took her out on the lake yesterday, to only have the same thing happen again; increased the throttle only to have the motor fall flat on it's face and start shaking violently again. It is kind of frustrating to say the least. The power pack that I replaced the first failed on with was a used power pack purchased on eBay. Now, it could be that this used power pack had seen it's better days and failed for one reason or another but it just seems odd that that would happen. I'm sure stranger things have happened but it just seems odd as previously stated.

I really don't know if this is related but when you set the throttle at say 3000 rpm, it will run there for a short time and then increase on it's own to about 4500 rpm and then start fluctuating back and forth every so often and will not stay running at one rpm setting!?

So, my question is: is there or could there be a possibility that there is an electrical problem of some sort that is causing these power packs to fail? When the motor is running, the voltage gauge on the dash is pegged out at 18 volts! Now I know that this is way to much voltage but the gauge may or may not be out of calibration. I really do not know how to go about checking for electrical problems if need be so any input about this would be greatly appreciated.

Thanks in advance..
 
Personally, I doubt the power pack is the fault at all. But just replacing them is not the answer. You need to check the system out properly with a DVA meter. The 18V is high, but probably not an issue with the running problem. The ignition system does not run off the battery or charging system.
 
Voltage To Powerpack Failures
(Magneto Capacitance Discharge Systems)
(J. Reeves)

The usual cause of having those type powerpacks fail repeatedly is having a very small of voltage applied to the Black/Yellow wire (Kill Circuit) at the pack. Test as follows.


Disconnect the Black/Yellow wire at the powerpack.


Insert either a ampere meter or a volt meter set to its lowest DC voltage reading between that Black Yellow wire and ground.


With the ignition key in the OFF position, observe the meter reading. Now turn the ignition key to the ON position and again observe the meter reading.


Any reading, movement of the meter needle, even a microvolt, would indicate that battery voltage is being applied to that Black/Yellow wire. If a reading is present, remove the other end of that Black/Yellow from the raised terminal of the ignition switch.


If the reading ceases to exist when the Black/Yellow wire is removed from the ignition switch, replace the switch. If the reading continues to exist, there would be a short of some kind in either the engine or instrument wiring harness.... to determine which, simply unplug the large RED electrical plug at the engine which would eliminate the instrument cable.

Note that the black/yellow wire must not have any other wire attached to it for the following reason!


Keep in mind that any accessory that has 12 volts running to it, especially when turned on, will have voltage flowing thru it and trailering out thru its black ground wire to complete the circuit. If that accessory has it's black ground wire attached to the "M" terminal that the black/yellow wire is attached to.... you will have voltage flowing directly to the powerpack.

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:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
Sorry it took so long to reply but I have been extremely busy and just got around to testing as you instructed. When I removed the cowling, I was looking for the black and yellow wire and noticed that the lower pin connection on the coil from the power pack was not attached all the way and was just loosely stuck on the pin. Could this be the culprit for the motor going into slow speed?
 
I also found that the tan sensor wire at the power pack had a bare spot. I would assume that if this was shorting to ground that it would activate the S.L.O.W. function. Is this logical?

Thanks
 
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