98 Yamaha 225 2 stroke (1 cyl. not firing )

[Team Reel Warriors]

While testing motor today, and while at WOT, the motor lost about 90% of power, but did not shut off. I idled over to a beach and let it sit awhile and cool off. When restarting, it showed what I thought was an over abundance of smoke on start-up and more smoke than normal on take off. Boat was idled to dock and transported to house. I immediately removed the plugs, which revealed no oil on top starboard plug, like it never fired at all, so I compression tested that cylinder and it showed 120psi.

Question: What does this situation bring to mind? And could someone offer me a starting point. I have a tournament to fish Saturday and am working hard to get her running right. Thanks.

[99yam40]

You need to test to see if you are getting spark to that cylinder
If you are then it is a fuel issue.

but one cylinder not firing will not cause 90% power drop.
You need to test the alarm system and then find out what alarm was coming in that brought in the safe mode if that is what happened

[Tucker]

What did you find warrior?

[PRMAKO26]

Seems to me that you have a bad ignition coil, cable or spark. Take all the spark cables off an insert a screwdriver in the one that you think is not fireing. Approach the screwdriver close to a metal part on the engine and try starting the engine. If you dont see the spark, then you have a bad cable or the coil is dead. If there is a spark, then the spark plug is dead.
My 2 cents

[jb123]

check comp on all cyls
have you done any fuel system service recently ?? ever ?
does your alarm system work correctly ?
digital or analog gauges ?