Johnson 40HP RDSL23 - positioning the coil & flywheel key /

[1962MFG/Johnson40hp]

Guys,
The answer to two questions will be gratefully received.

1) I replaced my plug leads so how do you set the position of the coils on the plate?
2) Any ideas why i have sheared two of the "woodruff" keys on the flywheel to shaft?

Thanks.

 

[Xcusme]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /

The coils should be aligned to the mounting bosses so that surface A and surface B are flush.

Shearing keys: You may not be torqeing down the flywheel nut to specfications. The flywheel taper is a dry fit, no lubrication of any kind.

 

[1962MFG/Johnson40hp]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /

thanks for the great info......... 105ft lb for the flywheel right?

 

[Paul Moir]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /

Yes that's correct. Where you've sheared the flywheel key a couple times, you'll want to refit the taper.
Click here

Once you've done that and torqued the nut properly, you won't shear another flywheel key again.

 

[1962MFG/Johnson40hp]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /

Great info, thanks.
I believe the shaft / flywheel fit is pretty chewed up. i'll dress and try again with a new key.
Question. why does the motor stop if the flywheel shears the key?

 

[Xcusme]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /

It's all about timings, the key indexes the flywheel and it's magnets. A sheared key throws everything outta whack. Spark is produced at the wrong time, commonly revealed by a backfireing motor etc.

 

[Paul Moir]

Re: Johnson 40HP RDSL23 - positioning the coil & flywheel key /


But on a Big Twin, the timing is governed by the cam on the crankshaft rather than the magnet on the flywheel. So rather than timing going out you loose spark completely because when the points open to initiate the spark, the ignition coil isn't magnetized because the magnet is somewhere else.
That's a simplified explanation but I think it is clearer.

A consequence of that is that if you've got the timing right you'll have a good spark too. None of that is true for outboards made after the mid 70s or so; then it happens just as Xcusme says. This is a very minor point but I spent too much time playing with these ignitions, and you did ask.