1973 9.5hp Johnson weak spark?

dfrants

Chief Petty Officer
Joined
Jul 26, 2008
Messages
404
what usually causes weak spark on an outboard with points? she starts and runs but not very well. loss of power and full speed and rough idle. tried testing the spark and I believe its weak...
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,450
Bad / cracked coils.---Dirty points.----Bad condensers.---Points opening at the wrong time.
 

dfrants

Chief Petty Officer
Joined
Jul 26, 2008
Messages
404
used a spark tester that you can set the gap. I tried it all the way down to 1/4" and could get it to jump. Tried an in-line tester, the one with a bulb in it. And that lights up.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
1/4" is good. But that does not mean the coils aren't cracked. Cracked coils can actually run----poorly and hard start.
 
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