PM 300 - wet and dark plug - help!

[Toffen]

Hi!
Number 5 runs dark and wet. The engine stumbles at idle now and then, but runs ok at cruise.
We have cleaned and blueprinted the injector (s), so that should be fine. Swopped the plug with another one, and the dark one went tan, and the tan went dark.
So something is wrong with the number 5. Tomorrow we will do a compression and leakdown test. Maybe its the ignition. Hope so!
I am confused as the engine runs ok at cruise (4.000 - 5.000 rpms), but stumbles at idle.
Any ideas??
Cheeers, Toffen G

[Sangster]

Sounds like a bad plug wire....

[Screaming Pete]

Could be a reed??

[Boatmaster]

Broken reed in the #5 reed cage would also be my thought. How many hours are on the motor, or how long since you did reeds last?

[DUCKY]

Also check the pulse width on the injector signal to that hole.