1956 Johnson RD-18 (No Spark)

[cmulchi]

Hello to everyone,

I am completing the restoration of a 1956 Johnson RD-18 and went to start up the unit for the first time last weekend. The motor would run momentarily and die, so I:
1) Rebuilt the carburator and put it back on.
2) Replaced fuel filter
3) Had also replaced the entire ignition system prior to removing the carburator including points, plugs, wires, and coils

After reassembling the motor, it now gets no spark to either cylinder and I had to remove the vacuum kill switch in order to remove the carb. The motor is getting fuel (removed spark plug and smelled gasoline as well as in the exhaust tube), but no spark. I am checking the vacuum line to the kill switch and will remove the ground lead from the kill switch to confirm. Am I missing anything else? The motor would run ok before the rebuild, so the ignition system was working then. Any help would e appreciated.
Thanks
Chuck

 

[F_R]

Re: 1956 Johnson RD-18 (No Spark)

The vacuum cut-out switch only works on one cylinder--the bottom one, I think. Anyhow, it can't kill the spark on both so look elsewhere. What you need to do is go back in and see what you did wrong. With everything new, it certainly should work---at least on one cylinder. You do have the breaker cam right side up, don't you? And the points gapped .020" at the high point on the cam? Coil wires goiing to the correct set of points? Did you use a torque wrench to tighten the flywheel nut to 60-65 foot pounds (sheared the key?)

OK, I'm guessing. Only you can see what's wrong.

 

[cmulchi]

Re: 1956 Johnson RD-18 (No Spark)

Thanks for the heads-up, I will check all of these items again.

In reassembling the flywheel, I did torque the flywheel, but will check over everything this weekend. As for the points, they were gapped at .020 as you specified (checked each point 3X before installing flywheel).

However, now that you mentioned it, I did notice something of interest during the re-installation of the flywheel. I very carefully aligned the key on the shaft with the notch in the flywheel and everything slipped into place ok. However, the flywheel seemed like it was .020"-.030" higher than before removal. I even pulled off the flywheel to check the key, but all looked OK. Have you ever seen this?

I will keep you posted adn thanks again.
Chuck

 

[lindy46]

Re: 1956 Johnson RD-18 (No Spark)

Make sure the shaft and the flywheel are perfectly clean before re-assembling. Make sure the coils are properly aligned with the bosses on the armature plate. If the coils aren't perfectly flush (pushed in too far) you may not get spark. If they are too far out, they will hit and the flywheel won't turn properly (could possibly cause damage).

 

[cmulchi]

Re: 1956 Johnson RD-18 (No Spark)

Lindy,
Thanks for the advice, I will clean the shaft and flywheel. The positioning of the coils I will also check. I did have some alignment issues when putting it back together orginally, but the motor fired right up but would not run continuously due to carbburator which I rebuilt as well. I will let you all know this weekend.
Chuck