Evinrude 90 running rough - only one cyl strong

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usedtoski

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I have an 87 Evinrude 90 that won't run smoothly. I'm not a professional but when I went to check the ignition wires I could see them arcing as I pulled each one off to check spark. I installed new ignition wires and plugs expecting the engine to run smoother, but was surprised when I still had the same rough running condition. If I remove the the plug wire from the cylinder at the top right (from the rear view), the engine stalls. I don't have the same thing happen with the other wires. Any simple fixes?
 
R

R.Johnson

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Re: Evinrude 90 running rough - only one cyl strong

Have you done a compression, and spark output test?
 
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Walker

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Re: Evinrude 90 running rough - only one cyl strong

I'd do what R.Johnson suggests, if that cheacks out then I'd do a complete carb overhaul on both carbs.
 
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usedtoski

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Re: Evinrude 90 running rough - only one cyl strong

Thanks for the reply. I'm not sure how to test the compression but I'll ask someone who knows.
 
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usedtoski

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Re: Evinrude 90 running rough - only one cyl strong

Originally posted by usedtoski:<br /> Thanks for the reply. I'm not sure how to test the compression but I'll ask someone who knows.
Click to expand...
 
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usedtoski

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Re: Evinrude 90 running rough - only one cyl strong

I did a compression test and the numbers were as follows: -------------------------------------<br /> 115 123 <br /><br />- 112 118 -<br /><br />Are these #s close enough? How do I do a spark test? Am I just pulling the wires off slightly and checking if there's spark or is there a way I should be checking the the amount of spark? Thank you for the advice so far. I really appreciate it that someone would give their time like that!
 
M

mikeyzx2

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Re: Evinrude 90 running rough - only one cyl strong

not only do you want to see how hot the spark is but also how far it'll jump. you can make one there's a post on here somewhere with a pic of a homemade tester. do a search on it
 
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Walker

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Re: Evinrude 90 running rough - only one cyl strong

Tear the carbs down, soak them in a suitable carb cleaner, blow them out with compressed air, check that every orifice, no matter how small, is clear. Reassemble with carb kits and I bet she'll run good.
 
G

G DANE

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Re: Evinrude 90 running rough - only one cyl strong

And BTW your compression numbers are fine.
 
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