spark but... on 9.5 Johnson '72

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Bill Peterson

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I have a 1972 9.5 johnson. I have replaced the points, condensers, and coils. Set everything to specs. When running, I can pull off the top plug wire and the motor does not cough or sputter, or die (it keeps running the same), which leads me to believe that cylinder is not working. I have good spark there. What is the next step?
 
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Rick.

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Re: spark but... on 9.5 Johnson '72

Switch your plugs and see if the problem follows the plug. Rick.
 
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Bill Peterson

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Re: spark but... on 9.5 Johnson '72

I will get a compression tester tomarrow. I also will switch the plugs and run it that way.thanks.
 
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crxess

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Re: spark but... on 9.5 Johnson '72

I'd say finish the test. With the motor running, pull the lower wire and see if it dies.

Compression test is always a good idea, but pick up a spark tester also. Just because points are new and set properly does not mean you have spark on htat cylinder. A single touch of a finger on a point surface can stop it from sparking. poor ground contact, same problem.

Make sure you have good spark over 1/4" or larger gap.
 
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Bill Peterson

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Re: spark but... on 9.5 Johnson '72

Compression test both cyl. at 65 psi.
Pulled lower spark plug when running- it dies.
Changed position of plugs same outcome.
I can't get spark to jump 1/4 inch on upper plug.
I will check points again, and replace plug wires.
 
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Rick.

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Re: spark but... on 9.5 Johnson '72

Your compression is fine for a 9.5. If your pulling the flywheel to check the points take the time to clean them with acetone or lacquer thinner. Your aware of how to gap the points when they are at the right place? If you fire it up at night you should be able to easily see any spark going to ground but a new set of plug wires would never hurt. They are probably original. Rick.
 
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Bill Peterson

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Re: spark but... on 9.5 Johnson '72

Yes, I set the points at TOP, Am installing new wires now. I cleaned the points with alcohol.
 
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Bill Peterson

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Re: spark but... on 9.5 Johnson '72

I think I've got it. Firing on both, ideling nice, will take it to lake this weekend.
 
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Rick.

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Re: spark but... on 9.5 Johnson '72

Hey that sounds great. I don't know what it is but I've come to believe the points on a 9.5 have no tolerance for being dirty or out of adjustment without giving you what for. Let us know how it works on the lake. Your final needle adjustment should be done while in the water and in gear. Rick.
 
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crxess

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Re: spark but... on 9.5 Johnson '72

In water at idle, Start at 2 1/2 turns out. Be patient. Adjust in 1/4 turn at a time. Allow time for the motor to catch up. Turn again and wait.
The motor should smooth back out each time and may pick up a few rpm's. Eventually while turning, the motor should sneeze. That is your cue to back out 1/8 or so and see of it smooths. May need a bit more out.

Take it for a spin and test the idle again to make sure you are not going to stall.

Remember, if your idle is mechanically to slow(Throttle plate completely closing) the motor is not going to stay running. Adjust the idle knob by the tiller if needed.
 
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