Ignition johnson 15r74g

[polotche]

Hi,
I want to known how to check my ignition on my 1974 johnson 15hp because I have no spark
thanks a lot

sorry for my language I m french

 

[racerone]

Remove flywheel.----Clean and set points at 0.020".---Test for spark again.-----No money spent test.

 

[polotche]

ok
thanks racerone, I testing this and I'm telling you again

 

[Crosbyman]

Hre are few instructions in French ….

première chose à faire c'est de débrancher le bouton d'arrêt qui peut-être défectueux et tuer l'ignition

il faut retirer la tête et aller nettoyer les pointes avec de l'acetone et une carte d'affaire ou pièce de papier rigide


il faudrait spécier si ce problème est apparu soudainement ou progressivement

il est rare que les deux circuits d'ignition tombent en panne ...ceci est indicatif d'un problème commun alors vérifiez bien le bouton d'arrêt

http://www.leeroysramblings.com/johnson_magneto.htm

 

[polotche]

Thanks Crosbyman
I buy this motor in out of order. So I search why it does not start

 

[racerone]

You are asking for some help.------" I tested this and i'm telling you again "-----What do you mean by that statement ?------Bring it over as I have everything that you might need to fix it .----No need for me to buy any parts to fix that simple motor !

 

[polotche]

We don't understand. I remove flywheel tomorrow and clean point. I will give you the result

 

[oldboat1]

Utilisez des condenseurs à pointe noire plus récents. Assurez-vous que les points sont parfaitement propres - l'acétone est un excellent nettoyant, appliqué avec une couverture d'allumettes.

 

[polotche]

HI,
I clean the point with acetone and set the points but I have no spark again.
I see the capacitor and the point are news
I join a photo

 

[Crosbyman]

that coil looks melted did you inspect the underside

 

[Crosbyman]

follow up… did you yes or no remove the kill switch and retest

did you yes or no … measure the coils secondary & primary resistance with a ohmmeter... post the values

did you yes or no .. inspect and/or redo / clean all wiring connections

did you yes or no try new plugs

 

[Crosbyman]

btw the top left corner of the coil looks burnt ???? if it is…... the secondary winding may be shorting out to ground …. or it could be jumping from the coil laminate to the flywheel ???

remove the coil and test the windings to see if the coils are shorted to the laminates ...measure OHMS between wires and laminate should see open .. infinite ….. nothing whatsoever

 

[racerone]

That does not look like an original style driver coil.-----So is it the correct replacement ?----Or something else.-----Is there a part # on it ?

 

[F_R]

Just for the record, there is no secondary winding in the driver coil. That all happens in the external spark coils

 

[oldboat1]

I see serious top abrasion (coil) from flywheel contact. The coil also appears to be in contact with the condenser (top of picture -- burnt area that Crosby mentions.)

I think the driver coil is either the incorrect one for your model, or is installed incorrectly. If there is a machined area on the mounting post, the edge of the coil lamination must be perfectly flush with the flat machined area.

[Edit. The BRP driver coil for your motor is part number 763784, and is available here at iBoats. The correct coil mounted correctly insures that the critical air gap to the magnet is correct]

 

[polotche]

I will try to answer everything The spark plug are news, the number of the driver coil is 511441



I measured the resistance and I find 0.5 between the primary and the secondary
1.6 for the primary
1.5 for the secondary

The coil touch the flywheel so I moved it

this ignition was tinkered before me so I try to do better

 

[racerone]

I say that is the wrong coil !!----You need a DRIVER COIL and only used on motors in the early / mid 1970's

 

[oldboat1]

The driver coil is here (#12): https://www.iboats.com/shop/engine-parts/1974-Johnson-15R74G-Magneto-Parts.html I believe I would just replace it, and make sure it is perfectly mounted.

(Also see post #14 re. your testing procedure.)

 

[Crosbyman]

F.R... true re driver coil and … I looked at the parts diagram

crow pie again...

 

[polotche]

I will buy a new coil drive with the good reference and I will tell you