1970 Johnson 9 1/2 HP - No Spark

[CT-Kurt]

I have a 1970 Johnson 9 1/2 HP outboard and can't get a spark from either cylinder. The points look good. I’ve tried disconnecting the stop switch and also jumpering out the stop switch wires, but no luck. It seams to me the only common circuit is the stop switch, but I’m not sure if this circuit needs to closed to run, or connected to ground?<br /><br />Any ideas?

 

[Paul Moir]

Re: 1970 Johnson 9 1/2 HP - No Spark

If there is two wires coming from the armature plate (where the spark plug wires come from) then they are connected together to kill spark on both cyls.. Grounding either one will kill spark in one cylinder. If they are left open (dangling), you should have spark.<br />If the engine hasn't been run in a long while, suspect the coils. If they are cracked (as they often are on these older johnny/rudes) then moisture has gotten in. New ones are cheap.<br />The only other thing I can think of would be if the flywheel key was sheared (the thing that keeps the flywheel at a certain place on the crankshaft). The magnet has to be in the right place when the points open (0.020 adjustment) for fire.<br />Good luck!

 

[CT-Kurt]

Re: 1970 Johnson 9 1/2 HP - No Spark

There are two wires coming from the armature plate. I pulled off the flywhell and the coils and condensors? look like new. The flywheel key is intact. I checked the points and they are at 0.020".<br /><br />Is there a way to check the coils or condensors with an Ohm meter?<br /><br />Thanks for your help!

 

[Paul Moir]

Re: 1970 Johnson 9 1/2 HP - No Spark

Sort of. The coils should have a resistance between the spark plug lead and ground of ~4K ohms. The other lead is around 1 ohm. Condensors should show no resistance. But these tests aren't very meaningful. The coil's generally fail from age (old pink ones cracked on the outside, letting in moisture or sparks out). Condensor failure is rare (especially on both!). Since the top plug ignition system is completely independant from the bottom, you should be looking at what is common to both.<br />I take it they're wasn't any oil residue on the contacts from a leaking top seal? They must be impeccably clean.<br />Is the flywheel magnet still strong?<br />Another shot in the dark: Have you ever known the ignition to work? Perhaps those new coils are set up wrong. They should be precisely flush with the machined boss they sit on, across it's face.

 

[Chinewalker]

Re: 1970 Johnson 9 1/2 HP - No Spark

A few things to check...<br /><br />Are the plugs grounded to the motor block when you're trying them? Are the plug wires properly seated in the coils? Are the spark plug boots clean and the sparkies (coiled plug connectors inside the boots) making good contact with the wire? Is the wire metallic core (automotive carbon core wires will not work!). Points are clean? You note that they're gapped at .020? Is this at the proper position? Gap should be set with the cam rider lined up with the crank key. Are the coils' wires (one to ground, one to the points) clear of the cam and tucked up under the coil so they don't get pinched? Is the armature plate excessively loose to the point that the points will open and close by moving it around?<br /><br />- Scott

 

[wayne h]

Re: 1970 Johnson 9 1/2 HP - No Spark

Is the armature plate excessively loose to the point that the points will open and close by moving it around?<br /><br />good point my 9.5 had a bad miss in it and the plate was lose changing my gap.<br /><br />also are the coils set right on the plate they should be lined up with the stand offs on the cam plate. this will make a diffrence if they are too far away. i think that evinrude states a good spark will shoot 7/16 gap. i did not think that was possible but it is my little 9.5 does it. get a spark tester at you local auto store they are cheap and will come in handy