This absolutely could be a carb issue among a number of other things (bad fuel pump diaphragm, dry rotted fuel hoses, dead cylinder) But the carb will have low speed jets and high speed jets. If the low speed is fine and but the high speed is clogged it could cause exactly the problem you're having. How many RPMs are you getting at WOT? If it's low then it could be the carb. If RPMs are high then its probably the prop.
"Life is a matter of luck and the odds of success are in no way enhanced by extreme caution." - Erich Topp, German U-boat Commander, 1943.
When in doubt, set the hook.