48 Special won't run above idle

[Teachaman]

I am the newest owner of this 48 special (1998), It starts great, idles fine, but won't get up to speed. Yesterday (the first time I ran it) it was fine, today, it won't wind up. I push the throttle forward it surges for a moment, then loses power. It runs fine if you don't want to go fast.

[boats.net]

Check the spark plugs, if problem persists, repair the carburetors.