Ingition Trouble, 1989 90HP 2 Stroke

[Invictus]

First off, thank you all for the posts on this site, endlessly useful information

The listed motor is "dropping" a cylinder after 3,000 RPM while underway. It does not instantly stop firing at 3,000 but after only a few moments or minutes above that mark.

When I back off the throttle to idle, the cylinder still does not fire for some time after the motor is left in neutral/idle. Plugs are in good order, wires in good order.

Ignition coil? Other issue?

Thank you,

Jason

[robert graham]

Maybe check fuel pump for bad diaphragm causing that cylinder to suck raw fuel and causing very rich mixture on that cylinder, fuel-fouling that plug. Remove fuel pump with 2 screws but leave fuel lines attached, then pump primer bulb and check for fuel coming out the back. Easy fix, $45 for whole new pump. Good Luck!

[99yam40]

It does sound fuel related or a bad plug. I would think that you could see which cylinder was having the problem by looking at the plugs.
but you can test the plugs for spark while problem is happening with a inductive timing light to make sure they each have steady spark.
If loosing spark then you would need to start testing for which failed.
If all the spark is good, Then it is looking at fuel/air mixture