'73' 40hp Johnson - no spark.

A friend gave me the above motor, with the words "it was working the last time he used it" but it has been lying up for some time.
I took the flywheel off and the coils were completely blown, I replaced them with what looked like a brand new pair off a 20hp, put it all back together and still nothing, no spark on either plug.

One thing I did do was make a new woodruff key for the crankshaft as the original was broken, I have since purchased a service manual and the key in the manual has a mark on it and it states that it should be put in the right way up.

I have also just printed off a link to tuning from kpa4303 and I am going to test the coils at the first opportunity.

I have also checked the diaphragm switch, the diaphragm is good, no pin holes.

Is there any way of checking the condensers with a ohm meter?

Any other ideas would be useful.

skipper711

Re: '73' 40hp Johnson - no spark.

Maybe this will help you out.
http://forums.iboats.com/engine-fre...-change-coils-set-points-old-omcs-294072.html

Re: '73' 40hp Johnson - no spark.

Assuming the coils are good, most no-spark problems are because the breaker points are dirty or corroded, or mis-adjusted

Re: '73' 40hp Johnson - no spark.

F_R,

What is the importance of the 'single upset mark' on the flywheel key, in my engineering training days we had exercises making woodruff keys and other keys, having a hard time understanding the upset mark.

skipper711