1979 Johnson 6hp spark on 1 cylinder

[ugmold]

I picked up a 1979 Johnson 6hp that had low compression. It HAD spark on both cylinders. I replaced the head gasket and it started right up, but had spark on only one cylinder.
I went thru and tested everything via this chart and advice from a youtube video.

At first it seemed to me that a new Powerpack would fix the problem (used known good). It did not.
I realized the reading I got on the brown to brown/yellow (charge coil/stator?) in the 20k OHM range on the multimeter was .57 not 450-600.
But I still had spark on the lower cylinder. I pulled apart the connector to swap the coil wires and found that the lower cylinder would spark on either connection but the top (which has an after market coil) would not. The coils check out fine. I also took the kill the switch out of the circuit just in case.
I hope this not too confusing. I am new to CDI ignitions.

 

[kbait]

Upper coil obviously not firing even with proper input from CDI. Replace coil. Aftermarket may have been a coil for a points motor, and is not compatible, even if it “ohms out” as good.

 

[ugmold]

Upper coil obviously not firing even with proper input from CDI. Replace coil. Aftermarket may have been a coil for a points motor, and is not compatible, even if it “ohms out” as good.

I did have spark initially on both. It also looks like other replacements I see listed. It does look cheap, small wiring.

 

[ugmold]

Upper coil obviously not firing even with proper input from CDI. Replace coil. Aftermarket may have been a coil for a points motor, and is not compatible, even if it “ohms out” as good.

Oh heck, I found a OEM used coil, I'll give it a try, hope you are right.

 

[ugmold]

Oh heck, I found a OEM used coil, I'll give it a try, hope you are right.

Well that didn't work, had intermittent spark, but no ohm reading on the voltmeter. So I returned it. It is odd but sometimes I get zapped with the motor at rest. And saw a spark unscrewing the "good" plug by hand with the plug wire attached.

 

[ugmold]

Well that didn't work, had intermittent spark, but no ohm reading on the voltmeter. So I returned it. It is odd but sometimes I get zapped with the motor at rest. And saw a spark unscrewing the "good" plug by hand with the plug wire attached.

I returned the faulty coil, and got another used oem coil from T-Mike Vintage Outboard (youtube channel) and everything works fine now. So KBait you were right, thanks.

 

[ct1762@gmail.com]

good lesson to learn: resistance tests only tell you if it needs to be replaced if out of spec. a good resistance test does NOT mean its putting out the proper running voltage.