1984 Johnson 9.9 - powerpack failure

[robgohn]

Hey folks, looking for some help.

My father gave me his 1984 Johnson 9.9 (J10RLCRA).
After somebody replaced the power pack our motor ran great (For 10 minutes).
Somehow father let the motor stall. When started up the engine again, only 1 spark plug was firing.

How did I find this out? After running the motor 10 minutes on both cylinders, and running again (but only 1 cylinder) for another 45 minutes. Back at home, I inspected both spark plugs. The top cylinder's spark plug looked clean, brand new. The spark plug was covered in gas, just not sparking. I then proceeded to inspect the bottom cylinder's spark plug. Brown tip, evidence that this spark plug was sparking.

Thinking the problem was just a faulty spark plug, I replaced the top cylinder's spark plug several times, all with the same result: motor running only on the bottom cylinder (replaced spark plug wires also). As a result, I started to believe that this was now an ignition coil issue. So I ordered the proper replacement coil assembly, replaced the coil, wired it up properly, went to the water with fingers crossed, and again, only running on the bottom cylinder. Damn.

Now im looking at this "replacement" powerpack. There are 4 wires going into the powerpack (2 brown from charge coil, 1 black and 1 white from sensor coil). There are 4 wires leaving the powerpack (ground, killswitch, 2 coil wires).

I did a few resistance tests on the wires going INTO the powerpack.
The sensor coil 40 ohm (perfect)
The charge coil 565 ohm (perfect)


Tommorrow morning, I will be taking voltage readings coming out of the sensor coil, charge coil, and powerpack to each coil to determine if there are any lower voltages than required.

It is possible this is a very simple fix, replace the powerpack. However, what could possibly ruin my brand new powerpack after 10 minutes? It is properly grounded and properly connected to the killswitch. Could something be wrong with either the sensor coil or the charge coil? if there was something wrong with either coil, wouldnt that mean that the engine wouldn't be able to run at all? (meaning the powerpack was not getting the juice)?

I will report back tomorrow with the voltage test measurements!

Any help / comments greatly appreciated!

Thank you,
Rob

 

[boobie]

Re: 1984 Johnson 9.9 - powerpack failure

Go through you tests and get back to us. You may just have a "bad" new power pack.

 

[Haffiman]

Re: 1984 Johnson 9.9 - powerpack failure

Which plugs are you using?

 

[robgohn]

Re: 1984 Johnson 9.9 - powerpack failure

Thanks for the timely replies!

Which plugs are you using?

I am currently using L77JC4 and QL77JC4 spark plugs. I will grab another new set (its always handy to have them in the emergency repair kit). Should I be using another plug? These plugs are brand new, the electrode tips are perfect, in general they look great. -- I will post the voltage test results in the morning.

 

[Haffiman]

Re: 1984 Johnson 9.9 - powerpack failure

Your plugs are ok, and not the culprit in this case.
Just a question to rule out any possibilities.
However do a check on your stop circuit. A partly 'leaking' stop button may kill the PP as well. Disconnect the GROUND connection from the stop button and use a multimeter to check for ANY voltage with engine running. With stop button pressed IN, you should have about 250Volts, with STOP in running pos(not pressed in) it must be zero!! Any voltage or pulses of voltage, replace the stop.

 

[robgohn]

Re: 1984 Johnson 9.9 - powerpack failure

Okay everyone thanks for help so far!

I did a few voltage tests on the wires going INTO the powerpack (pulled ropestart, no gas connected, propeller not in water). The tests were done on both of the wires coming from the sensor coil (2 brown), and both wires coming from the charge coil (1 black and 1 white) in the following order:

(------- represents wire)
sensor coil wire 1--->----->----->----DVM probe1--->----->----->----DVM probe2--->----->----->----powerpack

result on all tests: a flicker up to high voltages, but only for a brief moment. I would have had more accurate and precise measurements, however we broke the rope to start the engine during the tests.
Now I must replace this too. Im hoping I can just buy one of the same size (maybe one meant for a lawn mower) at Canadian Tire/ Home Depot. Any comments/suggestions on replacing the rope pull start?

As far as the connection to the killswitch goes, I am now looking to replace the killswitch altogether. I checked the BRP parts catalouge to identify the actual part number of the switch I need. 0389856 grounding switch assembly. However,
it costs $45 ! Im hoping I can just replace it with any industrial push button switch, could I not? I dont see any reason why I couldn't replace it with a $5 push button switch. Any thoughts on this?

Thanks again, all comments and information appreciated!

Rob

 

[robgohn]

Re: 1984 Johnson 9.9 - powerpack failure

In the Johnson service manual someone has lent me, it says the voltage test results should be:

Sensor coil 1.5V
Charge coil 250V

to measure these voltages properly, do I put DVM probe1 on SENSORwire1 and DVM probe2 on SENSORwire2?
or do i put both probes on one wire at a time, and measure them as individuals, meausing the voltage in each wire, independent of the other wire's voltages?

and the same for the charge coil! do I put DVM probe1 on CHARGEwire1 and DVM probe2 on CHARGEwire2?
or do i put both probes on one wire at a time, and measure them as individuals, meausing the voltage in each wire again?

 

[Haffiman]

Re: 1984 Johnson 9.9 - powerpack failure

Measure between the leads.