Yamaha 150 surging

[olddog44]

I have dual 1989 150hp on my 23' Steigercraft. the port counter rotating engine runs fine except around 3300rpm, where it surges to 3400-3500rpm then drops back to 3300rpm. above and below this range it runs well. Stb engine runs OK. I've changed fuel filters and fuel lines and used carb cleaner. any thoughts?
thanks

[jb123]

clean carbs