VMax 150 power loss

I have a 2002 Yamaha VMax 150. The last year I ran it frequently was 2004 and it ran great. I only ran it twice in 2005 (without any fuel stabilizer), then added Stabil in January of 2006. When I tried to use it in April of 2006, it acted a bit sluggish. I did not use it again until August and it ran horrible. There did appear to be quite a bit of water in the fuel bowl, but emptying and repriming didn't help. I ran 2 tanks of fuel (25 gal tank), each with octane booster, marine fuel drier, carbureator cleaner and Stabil through it. I completely drained the tank, carbureators, and fuel lines then let it sit until now (March 2007). I cleaned all three carbureators (didn't disassemble) with spray cleaner, checked the spark plugs (all clean), half filled the tank with premium, fuel drier, and carbureator cleaner. I ran all of that fuel through with minimal difference. The choke is working properly, but when the motor is warm, continually running "choke/no choke" raises my speed and rpm's. The boat was previously running 65 mph @6000rpm's. Now it is only running about 30 mph @3200 rpm's and only "playing with" the choke.

Re: VMax 150 power loss

Time to get serious about that fuel restriction and competly disassemble and rebuild the carbs. I would also replace the fuel pumps. Playing with all of the chemicals and continuing to run will only result in a broken powerhead.