92 Yamaha 40 Precision Blend Running Rough

Although some improvement, the 40 runs rougher than I think it should. Recently when I get started, after warming up the engine, as I push above say 60% throttle I get this ugly sounding miss. I back off and pump the throttle say 6, 7, or 10 times and the miss goes away. I have to do this routine several times and then it runs like a rocket the rest of the day. Miss never returns - it's more like a blaahahhhah, than a miss.

I think I need to pull the carbs and clean them out w/ solvent and compressed air. Besides little weed eaters and my Mantis tiller, I have never done that. How difficult to remove and clean? How difficult to rebuild? I have Seloc and Chilton manuals but they are very general and no way specific to my motor. SHoudl I buy a genunine official Yamaha shop manual for this motor ?

thanks