Only half throttle?

[Timberdoodle]

I've got an old Evinrude 5 hp Fisherman that starts, idles, and runs like a top at low rpm. Recently it decided it doesn't want to run at full throttle - just like that!
I examined the linkage under the hood and nothing seems obstructed. So, I think its in the carb or bowl or???
Of course, a king with my name on it is heading towards my favorite hole off the Cowlitz. Thanks for heading me in any direction you can think of. John

[Boat Doc']

I think that is a 2 cylinder, check plugs and spark, it may be plugs, points or coil. If it has good spark then check the carb. If it's a single cylinder check the carb.