84 4hp problem

[huntbirds]

my 84 4hp only runs at maybe 50% power. I have cleaned the carb and it seems fine. It gets good gas as I have put a clear tube from pump to carb. It runs good at low speeds but when I throttle up it only seems to go at maybe 50 %. Sometimes it revs up for a second but backs down to the 50%. Any thoughts?

[highcountry]

What do the plugs look like? It sounds like they are going to tell the story. Compare them and then check them against a good plug chart, it should tell you if one cylinder is having a fuel or spark issue.