No spark on one out of two plugs

Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
'72 50 HP Johnson decided to pull my plugs then put them back into the boots and see what the spark looks like. Only my top cylinder plug was firing a good blue spark, my bottom plug...nothing. I then switched them to see if it was a bad plug, still no fire on the bottom cylinder. What could be wrong?!

Oh, and one of the plugs shocked the crap outta me when I was holding them, and I was holding them by the boots so I don't know why it shocked me. Wife got a kick outta that though:rolleyes:
 

Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
Re: No spark on one out of two plugs

'72 50 HP Johnson decided to pull my plugs then put them back into the boots and see what the spark looks like. Only my top cylinder plug was firing a good blue spark, my bottom plug...nothing. I then switched them to see if it was a bad plug, still no fire on the bottom cylinder. What could be wrong?!

Oh, and one of the plugs shocked the crap outta me when I was holding them, and I was holding them by the boots so I don't know why it shocked me. Wife got a kick outta that though:rolleyes:


Update: Hmmm...that's interesting, I swapped the coils around and now I get good spark at both plugs. So, what does that mean? Leave coils as is, are the coils cylinder specific?
 

Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
Re: No spark on one out of two plugs

Update: Hmmm...that's interesting, I swapped the coils around and now I get good spark at both plugs. So, what does that mean? Leave coils as is, are the coils cylinder specific?

anybody?
 

tx1961whaler

Vice Admiral
Joined
May 31, 2008
Messages
5,197
Re: No spark on one out of two plugs

You probably fixed a loose or dirty connection by moving the coils around. I'd go back and make sure all of the connections are clean and shiny. It is also possible that one of the wires is actually broken and by moving it it temporarily fixed itself.
 

Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
Re: No spark on one out of two plugs

You probably fixed a loose or dirty connection by moving the coils around. I'd go back and make sure all of the connections are clean and shiny. It is also possible that one of the wires is actually broken and by moving it it temporarily fixed itself.

Awsome...hope that is the case...this boat and motor have been wrapped in so much prayer! Are the coils cylinder specific or does it matter?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: No spark on one out of two plugs

No. Coils will work on any cylinder.
 

1946Zephyr

Vice Admiral
Joined
Oct 21, 2008
Messages
5,556
Re: No spark on one out of two plugs

Also check the connections in the spark plug boots too.
 
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