2000 40hp 4 stroke loss of power at high speed

motor sat for years. gas lines were varnished. replaced gas lines, cleaned tank with filter, repaced gas filter. Pumped sea foam in it and let it sit for a couple of days. started it up and ran it for a few minutes. put fresh gas in and it runs. checked spark and its good.confirmed gas is getting to carbs. in neutral it idles fine and I can lift the lever to incease idle speed and it revs up and sounds great. take it out and put in gear low speed is fine but upper speed it bogs down and I have to back the throttle down to keepit alive. lower speed no problem. any ideas ?thank you

High speed jets need to be cleaned i believe.Possible that carbs need to be removed ,inspected and rebuilt,16 years old!

That's what I was wondering,thanks for input