Evinrude E-NATION, for those dedicated to water, power, fishing and fun
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Skipper
Posts: 12
Registered: ‎06-04-2019

15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

I have no idea what the reading should be ohm wise on the coils of this motor.  Red Test Lead to primary and Black Test Lead to Spark plug side of the Coil reads exactly the same on both coils at 10,000 + ohms.  That just seems real high to me?

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Captain
Posts: 151
Registered: ‎08-11-2011

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

Do you have spark? That model and 1974 were the worst for erratic ignition due to armature plate wobble. There was a kit available in its days to improve this. Probably NLA.

 

The system had points, power coil under flywheel and external coils. The power coil made 230-240 volts supplied to the external coils which in turn made 30-40,000 volts.

 

Make sure to file and clean points, this was a weak spot, as well as using a timing light to adjust timing. Timing adjustments were done with the points.

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Skipper
Posts: 12
Registered: ‎06-04-2019

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

I put a little fuel in each cylinder and did not even get a pop.  Thank you for letting me know about the eratic ignition on the 15R75C.  Makes me wish I did not pick that one up, ha ha, too late now.  

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Skipper
Posts: 12
Registered: ‎06-04-2019

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

I had such a high ohm reading on the two coils, I felt for sure they were bad, but I am not a mechanic so am not sure on this one.  Sounds like the motor has inherent problems from the time of its mfg.

 

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Captain
Posts: 146
Registered: ‎10-21-2015

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

Secondary resistance of 10K ohms sounds about right.  It would be a real surprise for two coils to simultaneously fail and fail with the same resistance reading.

 

Magneto ignitions are pretty basic and have been around for a long time.  Items to check are:  Magnets still exhibit magnetism, air gap between primary coil under flywheel and the magnets, points in good condition as previously pointed out, condensers are functioning, and finally primary resistance of ignition coil.

 

For maximum spark energy, it is important that the points break (open) at the moment current in the flywheel coil reaches a maximum value.

ElderSparky



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Admiral
Posts: 8,568
Registered: ‎07-14-2011

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

The driver coil under the flywheel and connected to the points was  a problem child in the early years of the 9.9 and 15. It was redesigned in '75 or '76 yet it could have the correct resistance but not operate as it should. After checking and testing all the other parts, replace the driver coil to be sure.

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


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Admiral
Posts: 8,568
Registered: ‎07-14-2011

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

 

 

 

 

 

1974-1976 ET driver coil specs.jpg

 

 

1974-1976 ET ignition coil specs.jpg

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


Highlighted
Skipper
Posts: 12
Registered: ‎06-04-2019

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

Sparky any idea what the ohm resistance should be on the stator and the driver coil?

 

Highlighted
Skipper
Posts: 12
Registered: ‎06-04-2019

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

Sparky thanks you caught the big ones on the driver coils and ignition coils.  Can you do that on the Stators also.

 

Highlighted
Admiral
Posts: 8,568
Registered: ‎07-14-2011

Re: 15 hp model 15R75C, 1975 Evinrude Coils have ohm reading of 10,000 plus

 

 

Give me some time to get an answer back.

 

We recommend that you order a service manual if you are going to do your own repairs.

 

www.outboardbooks.com

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



***************

The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.