1997 Yamaha 200hp SW2 weak/no spark on all 3 cylinders on port bank. Please help!!!!

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Coreye2044

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Feb 25, 2013
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I have been chasing a surging issue at idle for a year now. The engine runs great at WOT. it sometimes runs fine at idle and then sometimes doesn't, it will surge. Things I have done


Compression test - everything fine @ 120 psi.
Rebuilt carbs
Link and sync
Adjust low speed jets to spec
Tested coils - there was some corrosion were the coils grounded/bolted to the CDI assembly so I wire brushed it off and still no difference.
Tested spark on port side and noticed there was very little to no spark on all three cylinders. When I say weak, I mean I had the spark gap on the tester almost touching and it was barely arching.
Tested spark on starboard side and spark was great. When I say great I mean gap of an inch would get good spark.

After the spark test it led me to believe this was the cause of the surging.
What I need help with is the next step. Should I test - CDI (is there a way to test?), stator, or is there a switch that kills those three cylinders when shifting in and out of gear? Any help would be highly appreciated.
Thanks!!!
 

Coreye2044

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Feb 25, 2013
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Re: 1997 Yamaha 200hp SW2 weak/no spark on all 3 cylinders on port bank. Please help!

Anybody out there?
 

decconspec

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Apr 13, 2016
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I have EXACTLY the same issue w/ EXACTLY the same engine! Did you ever figure out the problem and get it taken care of? I'm thinking the stator but would really appreciate knowing what you came up with. Thanks in advance
 

GA_Boater

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May 24, 2011
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Please the Help Tip on top of the page and start a new thread. This one is from 2013 and is inactive. Starting a new thread is the best way to achieve results and get your motor running right.

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