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Captain Dave
Captain Dave, Marine Mechanic
Category: Boat
Satisfied Customers: 3847
Experience:  USCG Licensed Captain, 20+ Years Boating, Fishing, Maintenance and Repair Experience
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I have a 2008 Yamaha 90hp 2 Stroke with NO SPARK. It has been

Customer Question

I have a 2008 Yamaha 90hp 2 Stroke with NO SPARK. It has been running great but when I went to start it the other day it would only cranks. The digital tach works, the hot horn works, all the fuses are good and I did not see a pulled connection under the helm. I tried disconnecting the yellow CDI bypass wire and still no spark. If you can solve this I am willing to pay the fee. The engine is immaculate with 130 hrs on it.
Submitted: 6 years ago.
Category: Boat
Expert:  Captain Dave replied 6 years ago.
Hello. One possibility is a failed key switch. There will be two terminals on the back labeled "M" - with the key turned to "on" (the runnign position) one should have continuity to ground and other should not. If both go to ground then they are shorted and the ignition system is grounded (that's how the engine is topped, by connecting the ignition to ground). You could also try removing one wire from an "M" terminal and see if you get spark - it you do that's the problem. If the motor starts, you will have to reconnect the wire to stop it. If the key switch is OK then the most likely other explanation for no spark (assuming all wiring is OK) is a failed CDI.
Customer: replied 6 years ago.
Thanks for the reply but the Yamaha key switch is waterproof, there are no terminals visible. What color are the wire (s) am I looking for?

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